ORM Internals — SQLAlchemy 1.2 Documentation

Release: 1.2.8 | Release Date: May 28, 2018

# SQLAlchemy 1.2 Documentation

# ORM Internals

Key ORM constructs, not otherwise covered in other sections, are listed here.

class `sqlalchemy.orm.state.` `AttributeState`(state, key)

  Provide an inspection interface corresponding to a particular attribute on a particular mapped object.

  The `AttributeState` object is accessed via the `InstanceState.attrs` collection of a particular `InstanceState`:

      from sqlalchemy import inspect

      insp = inspect(some_mapped_object)
      attr_state = insp.attrs.some_attribute

  `history`

    Return the current pre-flush change history for this attribute, via the `History` interface.

    This method will not emit loader callables if the value of the attribute is unloaded.

    See also

    `AttributeState.load_history()` - retrieve history using loader callables if the value is not locally present.

    `attributes.get_history()` - underlying function

  `load_history`()

    Return the current pre-flush change history for this attribute, via the `History` interface.

    This method will emit loader callables if the value of the attribute is unloaded.

    See also

    `AttributeState.history`

    `attributes.get_history()` - underlying function

    New in version 0.9.0.

  `loaded_value`

    The current value of this attribute as loaded from the database.

    If the value has not been loaded, or is otherwise not present in the object’s dictionary, returns NO_VALUE.

  `value`

    Return the value of this attribute.

    This operation is equivalent to accessing the object’s attribute directly or via `getattr()`, and will fire off any pending loader callables if needed.

class `sqlalchemy.orm.util.` `CascadeOptions`

  Bases: `builtins.frozenset`

  Keeps track of the options sent to relationship().cascade

class `sqlalchemy.orm.instrumentation.` `ClassManager`(class_)

  Bases: `builtins.dict`

  tracks state information at the class level.

  `__le__`
    inherited from the `__le__` attribute of `dict`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `dict`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `dict`

    Return self!=value.

  `clear`() → None. Remove all items from D.
    inherited from the `clear()` method of `dict`
  `copy`() → a shallow copy of D
    inherited from the `copy()` method of `dict`
  `dispose`()

    Dissasociate this manager from its class.

  `fromkeys`()
    inherited from the `fromkeys()` method of `dict`

    Returns a new dict with keys from iterable and values equal to value.

  `get`(k[, d]) → D[k] if k in D, else d. d defaults to None.
    inherited from the `get()` method of `dict`
  `has_parent`(state, key, optimistic=False)

    TODO

  `items`() → a set-like object providing a view on D's items
    inherited from the `items()` method of `dict`
  `keys`() → a set-like object providing a view on D's keys
    inherited from the `keys()` method of `dict`
  `manage`()

    Mark this instance as the manager for its class.

  `original_init`

    Initialize self. See help(type(self)) for accurate signature.

  `pop`(k[, d]) → v, remove specified key and return the corresponding value.
    inherited from the `pop()` method of `dict`

    If key is not found, d is returned if given, otherwise KeyError is raised

  `popitem`() → (k, v), remove and return some (key, value) pair as a
    inherited from the `popitem()` method of `dict`

    2-tuple; but raise KeyError if D is empty.

  `setdefault`(k[, d]) → D.get(k,d), also set D[k]=d if k not in D
    inherited from the `setdefault()` method of `dict`
  `state_getter`()

    Return a (instance) -> InstanceState callable.

    “state getter” callables should raise either KeyError or AttributeError if no InstanceState could be found for the instance.

  `unregister`()

    remove all instrumentation established by this ClassManager.

  `update`([E, ]**F) → None. Update D from dict/iterable E and F.
    inherited from the `update()` method of `dict`

    If E is present and has a .keys() method, then does: for k in E: D[k] = E[k] If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k]

  `values`() → an object providing a view on D's values
    inherited from the `values()` method of `dict`

class `sqlalchemy.orm.properties.` `ColumnProperty`(*columns, **kwargs)

  Bases: `sqlalchemy.orm.interfaces.StrategizedProperty`

  Describes an object attribute that corresponds to a table column.

  Public constructor is the `orm.column_property()` function.

  class `Comparator`(prop, parentmapper, adapt_to_entity=None)

    Bases: `sqlalchemy.util.langhelpers.MemoizedSlots`, `sqlalchemy.orm.interfaces.PropComparator`

    Produce boolean, comparison, and other operators for `ColumnProperty` attributes.

    See the documentation for `PropComparator` for a brief overview.

    See also:

    `PropComparator`

    `ColumnOperators`

    Redefining and Creating New Operators

    `TypeEngine.comparator_factory`

    `__eq__`(other)
      inherited from the `__eq__()` method of `ColumnOperators`

      Implement the `==` operator.

      In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

    `__le__`(other)
      inherited from the `__le__()` method of `ColumnOperators`

      Implement the `<=` operator.

      In a column context, produces the clause `a <= b`.

    `__lt__`(other)
      inherited from the `__lt__()` method of `ColumnOperators`

      Implement the `<` operator.

      In a column context, produces the clause `a < b`.

    `__ne__`(other)
      inherited from the `__ne__()` method of `ColumnOperators`

      Implement the `!=` operator.

      In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

    `adapt_to_entity`(adapt_to_entity)
      inherited from the `adapt_to_entity()` method of `PropComparator`

      Return a copy of this PropComparator which will use the given `AliasedInsp` to produce corresponding expressions.

    `adapter`
      inherited from the `adapter` attribute of `PropComparator`

      Produce a callable that adapts column expressions to suit an aliased version of this comparator.

    `all_`()
      inherited from the `all_()` method of `ColumnOperators`

      Produce a `all_()` clause against the parent object.

      This operator is only appropriate against a scalar subquery object, or for some backends an column expression that is against the ARRAY type, e.g.:

          # postgresql '5 = ALL (somearray)'
          expr = 5 == mytable.c.somearray.all_()

          # mysql '5 = ALL (SELECT value FROM table)'
          expr = 5 == select([table.c.value]).as_scalar().all_()

      See also

      `all_()` - standalone version

      `any_()` - ANY operator

      New in version 1.1.

    `any`(criterion=None, **kwargs)
      inherited from the `any()` method of `PropComparator`

      Return true if this collection contains any member that meets the given criterion.

      The usual implementation of `any()` is `RelationshipProperty.Comparator.any()`.

      Parameters: | criterion – an optional ClauseElement formulated against the member class’ table or attributes. **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.

    `any_`()
      inherited from the `any_()` method of `ColumnOperators`

      Produce a `any_()` clause against the parent object.

      This operator is only appropriate against a scalar subquery object, or for some backends an column expression that is against the ARRAY type, e.g.:

          # postgresql '5 = ANY (somearray)'
          expr = 5 == mytable.c.somearray.any_()

          # mysql '5 = ANY (SELECT value FROM table)'
          expr = 5 == select([table.c.value]).as_scalar().any_()

      See also

      `any_()` - standalone version

      `all_()` - ALL operator

      New in version 1.1.

    `asc`()
      inherited from the `asc()` method of `ColumnOperators`

      Produce a `asc()` clause against the parent object.

    `between`(cleft, cright, symmetric=False)
      inherited from the `between()` method of `ColumnOperators`

      Produce a `between()` clause against the parent object, given the lower and upper range.

    `bool_op`(opstring, precedence=0)
      inherited from the `bool_op()` method of `Operators`

      Return a custom boolean operator.

      This method is shorthand for calling `Operators.op()` and passing the `Operators.op.is_comparison` flag with True.

      New in version 1.2.0b3.

      See also

      `Operators.op()`

    `collate`(collation)
      inherited from the `collate()` method of `ColumnOperators`

      Produce a `collate()` clause against the parent object, given the collation string.

      See also

      `collate()`

    `concat`(other)
      inherited from the `concat()` method of `ColumnOperators`

      Implement the ‘concat’ operator.

      In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

    `contains`(other, **kwargs)
      inherited from the `contains()` method of `ColumnOperators`

      Implement the ‘contains’ operator.

      Produces a LIKE expression that tests against a match for the middle of a string value:

          column LIKE '%' || <other> || '%'

      E.g.:

          stmt = select([sometable]).\
              where(sometable.c.column.contains("foobar"))

      Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.contains.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.contains.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

      - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.contains.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
            somecolumn.contains("foo%bar", autoescape=True)
        Will render as:
            somecolumn LIKE '%' || :param || '%' ESCAPE '/'
      - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.contains.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.contains.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
            somecolumn.contains("foo/%bar", escape="^")
        Will render as:
            somecolumn LIKE '%' || :param || '%' ESCAPE '^'
        The parameter may also be combined with `ColumnOperators.contains.autoescape`:
            somecolumn.contains("foo%bar^bat", escape="^", autoescape=True)
      Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

      See also

      `ColumnOperators.startswith()`

      `ColumnOperators.endswith()`

      `ColumnOperators.like()`

    `desc`()
      inherited from the `desc()` method of `ColumnOperators`

      Produce a `desc()` clause against the parent object.

    `distinct`()
      inherited from the `distinct()` method of `ColumnOperators`

      Produce a `distinct()` clause against the parent object.

    `endswith`(other, **kwargs)
      inherited from the `endswith()` method of `ColumnOperators`

      Implement the ‘endswith’ operator.

      Produces a LIKE expression that tests against a match for the end of a string value:

          column LIKE '%' || <other>

      E.g.:

          stmt = select([sometable]).\
              where(sometable.c.column.endswith("foobar"))

      Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.endswith.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.endswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

      - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.endswith.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
            somecolumn.endswith("foo%bar", autoescape=True)
        Will render as:
            somecolumn LIKE '%' || :param ESCAPE '/'
      - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.endswith.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.endswith.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
            somecolumn.endswith("foo/%bar", escape="^")
        Will render as:
            somecolumn LIKE '%' || :param ESCAPE '^'
        The parameter may also be combined with `ColumnOperators.endswith.autoescape`:
            somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)
      Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

      See also

      `ColumnOperators.startswith()`

      `ColumnOperators.contains()`

      `ColumnOperators.like()`

    `has`(criterion=None, **kwargs)
      inherited from the `has()` method of `PropComparator`

      Return true if this element references a member which meets the given criterion.

      The usual implementation of `has()` is `RelationshipProperty.Comparator.has()`.

      Parameters: | criterion – an optional ClauseElement formulated against the member class’ table or attributes. **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.

    `ilike`(other, escape=None)
      inherited from the `ilike()` method of `ColumnOperators`

      Implement the `ilike` operator, e.g. case insensitive LIKE.

      In a column context, produces an expression either of the form:

          lower(a) LIKE lower(other)

      Or on backends that support the ILIKE operator:

          a ILIKE other

      E.g.:

          stmt = select([sometable]).\
              where(sometable.c.column.ilike("%foobar%"))

      - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
            somecolumn.ilike("foo/%bar", escape="/")

      See also

      `ColumnOperators.like()`

    `in_`(other)
      inherited from the `in_()` method of `ColumnOperators`

      Implement the `in` operator.

      In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

      In the case that `other` is an empty sequence, the compiler produces an “empty in” expression. This defaults to the expression “1 != 1” to produce false in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

      Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.notin_()` operators now produce a “static” expression for an empty IN sequence by default.

    `is_`(other)
      inherited from the `is_()` method of `ColumnOperators`

      Implement the `IS` operator.

      Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

      New in version 0.7.9.

      See also

      `ColumnOperators.isnot()`

    `is_distinct_from`(other)
      inherited from the `is_distinct_from()` method of `ColumnOperators`

      Implement the `IS DISTINCT FROM` operator.

      Renders “a IS DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS NOT b”.

      New in version 1.1.

    `isnot`(other)
      inherited from the `isnot()` method of `ColumnOperators`

      Implement the `IS NOT` operator.

      Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

      New in version 0.7.9.

      See also

      `ColumnOperators.is_()`

    `isnot_distinct_from`(other)
      inherited from the `isnot_distinct_from()` method of `ColumnOperators`

      Implement the `IS NOT DISTINCT FROM` operator.

      Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

      New in version 1.1.

    `like`(other, escape=None)
      inherited from the `like()` method of `ColumnOperators`

      Implement the `like` operator.

      In a column context, produces the expression:

          a LIKE other

      E.g.:

          stmt = select([sometable]).\
              where(sometable.c.column.like("%foobar%"))

      - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
            somecolumn.like("foo/%bar", escape="/")

      See also

      `ColumnOperators.ilike()`

    `match`(other, **kwargs)
      inherited from the `match()` method of `ColumnOperators`

      Implements a database-specific ‘match’ operator.

      `match()` attempts to resolve to a MATCH-like function or operator provided by the backend. Examples include:

      - PostgreSQL - renders `x @@ to_tsquery(y)`
      - MySQL - renders `MATCH (x) AGAINST (y IN BOOLEAN MODE)`
      - Oracle - renders `CONTAINS(x, y)`
      - other backends may provide special implementations.
      - Backends without any special implementation will emit the operator as “MATCH”. This is compatible with SQlite, for example.
    `notilike`(other, escape=None)
      inherited from the `notilike()` method of `ColumnOperators`

      implement the `NOT ILIKE` operator.

      This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

      New in version 0.8.

      See also

      `ColumnOperators.ilike()`

    `notin_`(other)
      inherited from the `notin_()` method of `ColumnOperators`

      implement the `NOT IN` operator.

      This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

      In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

      Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.notin_()` operators now produce a “static” expression for an empty IN sequence by default.

      See also

      `ColumnOperators.in_()`

    `notlike`(other, escape=None)
      inherited from the `notlike()` method of `ColumnOperators`

      implement the `NOT LIKE` operator.

      This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

      New in version 0.8.

      See also

      `ColumnOperators.like()`

    `nullsfirst`()
      inherited from the `nullsfirst()` method of `ColumnOperators`

      Produce a `nullsfirst()` clause against the parent object.

    `nullslast`()
      inherited from the `nullslast()` method of `ColumnOperators`

      Produce a `nullslast()` clause against the parent object.

    `of_type`(class_)
      inherited from the `of_type()` method of `PropComparator`

      Redefine this object in terms of a polymorphic subclass.

      Returns a new PropComparator from which further criterion can be evaluated.

      e.g.:

          query.join(Company.employees.of_type(Engineer)).\
             filter(Engineer.name=='foo')

      Parameters: | class_ – a class or mapper indicating that criterion will be against this specific subclass.

      See also

      Referring to specific subtypes on relationships

    `op`(opstring, precedence=0, is_comparison=False, return_type=None)
      inherited from the `op()` method of `Operators`

      produce a generic operator function.

      e.g.:

          somecolumn.op("*")(5)

      produces:

          somecolumn * 5

      This function can also be used to make bitwise operators explicit. For example:

          somecolumn.op('&')(0xff)

      is a bitwise AND of the value in `somecolumn`.

      Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument. is_comparison – if True, the operator will be considered as a “comparison” operator, that is which evaluates to a boolean true/false value, like `==`, `>`, etc. This flag should be set so that ORM relationships can establish that the operator is a comparison operator when used in a custom join condition. New in version 0.9.2: - added the `Operators.op.is_comparison` flag. return_type – a `TypeEngine` class or object that will force the return type of an expression produced by this operator to be of that type. By default, operators that specify `Operators.op.is_comparison` will resolve to `Boolean`, and those that do not will be of the same type as the left-hand operand. New in version 1.2.0b3: - added the `Operators.op.return_type` argument.

      See also

      Redefining and Creating New Operators

      Using custom operators in join conditions

    `operate`(op, *other, **kwargs)

      Operate on an argument.

      This is the lowest level of operation, raises `NotImplementedError` by default.

      Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding `ColumnOperators` to apply `func.lower()` to the left and right side:

          class MyComparator(ColumnOperators):
              def operate(self, op, other):
                  return op(func.lower(self), func.lower(other))

      Parameters: | op – Operator callable. *other – the ‘other’ side of the operation. Will be a single scalar for most operations. **kwargs – modifiers. These may be passed by special operators such as `ColumnOperators.contains()`.

    `reverse_operate`(op, other, **kwargs)

      Reverse operate on an argument.

      Usage is the same as `operate()`.

    `startswith`(other, **kwargs)
      inherited from the `startswith()` method of `ColumnOperators`

      Implement the `startswith` operator.

      Produces a LIKE expression that tests against a match for the start of a string value:

          column LIKE <other> || '%'

      E.g.:

          stmt = select([sometable]).\
              where(sometable.c.column.startswith("foobar"))

      Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.startswith.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.startswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

      - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.startswith.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
            somecolumn.startswith("foo%bar", autoescape=True)
        Will render as:
            somecolumn LIKE :param || '%' ESCAPE '/'
      - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.startswith.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.startswith.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
            somecolumn.startswith("foo/%bar", escape="^")
        Will render as:
            somecolumn LIKE :param || '%' ESCAPE '^'
        The parameter may also be combined with `ColumnOperators.startswith.autoescape`:
            somecolumn.startswith("foo%bar^bat", escape="^", autoescape=True)
      Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

      See also

      `ColumnOperators.endswith()`

      `ColumnOperators.contains()`

      `ColumnOperators.like()`

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__init__`(*columns, **kwargs)

    Construct a new `ColumnProperty` object.

    This constructor is mirrored as a public API function; see `column_property()` for a full usage and argument description.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `cascade_iterator`(type_, state, visited_instances=None, halt_on=None)
    inherited from the `cascade_iterator()` method of `MapperProperty`

    Iterate through instances related to the given instance for a particular ‘cascade’, starting with this MapperProperty.

    Return an iterator3-tuples (instance, mapper, state).

    Note that the ‘cascade’ collection on this MapperProperty is checked first for the given type before cascade_iterator is called.

    This method typically only applies to RelationshipProperty.

  `class_attribute`
    inherited from the `class_attribute` attribute of `MapperProperty`

    Return the class-bound descriptor corresponding to this `MapperProperty`.

    This is basically a `getattr()` call:

        return getattr(self.parent.class_, self.key)

    I.e. if this `MapperProperty` were named `addresses`, and the class to which it is mapped is `User`, this sequence is possible:

        >>> from sqlalchemy import inspect
        >>> mapper = inspect(User)
        >>> addresses_property = mapper.attrs.addresses
        >>> addresses_property.class_attribute is User.addresses
        True
        >>> User.addresses.property is addresses_property
        True

  `create_row_processor`(context, path, mapper, result, adapter, populators)
    inherited from the `create_row_processor()` method of `StrategizedProperty`

    Produce row processing functions and append to the given set of populators lists.

  `do_init`()

    Perform subclass-specific initialization post-mapper-creation steps.

    This is a template method called by the `MapperProperty` object’s init() method.

  `expression`

    Return the primary column or expression for this ColumnProperty.

  `extension_type` = symbol('NOT_EXTENSION')
  `init`()
    inherited from the `init()` method of `MapperProperty`

    Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.

  `instrument_class`(mapper)

    Hook called by the Mapper to the property to initiate instrumentation of the class attribute managed by this MapperProperty.

    The MapperProperty here will typically call out to the attributes module to set up an InstrumentedAttribute.

    This step is the first of two steps to set up an InstrumentedAttribute, and is called early in the mapper setup process.

    The second step is typically the init_class_attribute step, called from StrategizedProperty via the post_instrument_class() hook. This step assigns additional state to the InstrumentedAttribute (specifically the “impl”) which has been determined after the MapperProperty has determined what kind of persistence management it needs to do (e.g. scalar, object, collection, etc).

  `merge`(session, source_state, source_dict, dest_state, dest_dict, load, _recursive, _resolve_conflict_map)

    Merge the attribute represented by this `MapperProperty` from source to destination object.

  `post_instrument_class`(mapper)
    inherited from the `post_instrument_class()` method of `StrategizedProperty`

    Perform instrumentation adjustments that need to occur after init() has completed.

    The given Mapper is the Mapper invoking the operation, which may not be the same Mapper as self.parent in an inheritance scenario; however, Mapper will always at least be a sub-mapper of self.parent.

    This method is typically used by StrategizedProperty, which delegates it to LoaderStrategy.init_class_attribute() to perform final setup on the class-bound InstrumentedAttribute.

  `set_parent`(parent, init)
    inherited from the `set_parent()` method of `MapperProperty`

    Set the parent mapper that references this MapperProperty.

    This method is overridden by some subclasses to perform extra setup when the mapper is first known.

  `setup`(context, entity, path, adapter, **kwargs)
    inherited from the `setup()` method of `StrategizedProperty`

    Called by Query for the purposes of constructing a SQL statement.

    Each MapperProperty associated with the target mapper processes the statement referenced by the query context, adding columns and/or criterion as appropriate.

class `sqlalchemy.orm.properties.` `ComparableProperty`(comparator_factory, descriptor=None, doc=None, info=None)

  Bases: `sqlalchemy.orm.descriptor_props.DescriptorProperty`

  Instruments a Python property for use in query expressions.

  `__init__`(comparator_factory, descriptor=None, doc=None, info=None)

    Construct a new `ComparableProperty` object.

    This constructor is mirrored as a public API function; see `comparable_property()` for a full usage and argument description.

class `sqlalchemy.orm.descriptor_props.` `CompositeProperty`(class_, *attrs, **kwargs)

  Bases: `sqlalchemy.orm.descriptor_props.DescriptorProperty`

  Defines a “composite” mapped attribute, representing a collection of columns as one attribute.

  `CompositeProperty` is constructed using the `composite()` function.

  See also

  Composite Column Types

  class `Comparator`(prop, parentmapper, adapt_to_entity=None)

    Bases: `sqlalchemy.orm.interfaces.PropComparator`

    Produce boolean, comparison, and other operators for `CompositeProperty` attributes.

    See the example in Redefining Comparison Operations for Composites for an overview of usage , as well as the documentation for `PropComparator`.

    See also:

    `PropComparator`

    `ColumnOperators`

    Redefining and Creating New Operators

    `TypeEngine.comparator_factory`

  class `CompositeBundle`(property, expr)

    Bases: `sqlalchemy.orm.query.Bundle`

    `create_row_processor`(query, procs, labels)

      Produce the “row processing” function for this `Bundle`.

      May be overridden by subclasses.

      See also

      Column Bundles - includes an example of subclassing.

  `__init__`(class_, *attrs, **kwargs)

    Construct a new `CompositeProperty` object.

    This constructor is mirrored as a public API function; see `composite()` for a full usage and argument description.

  `do_init`()

    Initialization which occurs after the `CompositeProperty` has been associated with its parent mapper.

  `get_history`(state, dict_, passive=symbol('PASSIVE_OFF'))

    Provided for userland code that uses attributes.get_history().

  `instrument_class`(mapper)

    Hook called by the Mapper to the property to initiate instrumentation of the class attribute managed by this MapperProperty.

    The MapperProperty here will typically call out to the attributes module to set up an InstrumentedAttribute.

    This step is the first of two steps to set up an InstrumentedAttribute, and is called early in the mapper setup process.

    The second step is typically the init_class_attribute step, called from StrategizedProperty via the post_instrument_class() hook. This step assigns additional state to the InstrumentedAttribute (specifically the “impl”) which has been determined after the MapperProperty has determined what kind of persistence management it needs to do (e.g. scalar, object, collection, etc).

class `sqlalchemy.orm.attributes.` `Event`(attribute_impl, op)

  A token propagated throughout the course of a chain of attribute events.

  Serves as an indicator of the source of the event and also provides a means of controlling propagation across a chain of attribute operations.

  The `Event` object is sent as the `initiator` argument when dealing with events such as `AttributeEvents.append()`, `AttributeEvents.set()`, and `AttributeEvents.remove()`.

  The `Event` object is currently interpreted by the backref event handlers, and is used to control the propagation of operations across two mutually-dependent attributes.

  New in version 0.9.0.

  Variables: | impl – The `AttributeImpl` which is the current event initiator. op – The symbol `OP_APPEND`, `OP_REMOVE`, `OP_REPLACE`, or `OP_BULK_REPLACE`, indicating the source operation.

class `sqlalchemy.orm.identity.` `IdentityMap`
  `check_modified`()

    return True if any InstanceStates present have been marked as ‘modified’.

class `sqlalchemy.orm.base.` `InspectionAttr`

  A base class applied to all ORM objects that can be returned by the `inspect()` function.

  The attributes defined here allow the usage of simple boolean checks to test basic facts about the object returned.

  While the boolean checks here are basically the same as using the Python isinstance() function, the flags here can be used without the need to import all of these classes, and also such that the SQLAlchemy class system can change while leaving the flags here intact for forwards-compatibility.

  `extension_type` = symbol('NOT_EXTENSION')

    The extension type, if any. Defaults to `interfaces.NOT_EXTENSION`

    New in version 0.8.0.

    See also

    `HYBRID_METHOD`

    `HYBRID_PROPERTY`

    `ASSOCIATION_PROXY`

  `is_aliased_class` = False

    True if this object is an instance of `AliasedClass`.

  `is_attribute` = False

    True if this object is a Python descriptor.

    This can refer to one of many types. Usually a `QueryableAttribute` which handles attributes events on behalf of a `MapperProperty`. But can also be an extension type such as `AssociationProxy` or `hybrid_property`. The `InspectionAttr.extension_type` will refer to a constant identifying the specific subtype.

    See also

    `Mapper.all_orm_descriptors`

  `is_clause_element` = False

    True if this object is an instance of `ClauseElement`.

  `is_instance` = False

    True if this object is an instance of `InstanceState`.

  `is_mapper` = False

    True if this object is an instance of `Mapper`.

  `is_property` = False

    True if this object is an instance of `MapperProperty`.

  `is_selectable` = False

    Return True if this object is an instance of `Selectable`.

class `sqlalchemy.orm.base.` `InspectionAttrInfo`

  Bases: `sqlalchemy.orm.base.InspectionAttr`

  Adds the `.info` attribute to `InspectionAttr`.

  The rationale for `InspectionAttr` vs. `InspectionAttrInfo` is that the former is compatible as a mixin for classes that specify `__slots__`; this is essentially an implementation artifact.

  `info`

    Info dictionary associated with the object, allowing user-defined data to be associated with this `InspectionAttr`.

    The dictionary is generated when first accessed. Alternatively, it can be specified as a constructor argument to the `column_property()`, `relationship()`, or `composite()` functions.

    New in version 0.8: Added support for .info to all `MapperProperty` subclasses.

    Changed in version 1.0.0: `MapperProperty.info` is also available on extension types via the `InspectionAttrInfo.info` attribute, so that it can apply to a wider variety of ORM and extension constructs.

    See also

    `QueryableAttribute.info`

    `SchemaItem.info`

class `sqlalchemy.orm.state.` `InstanceState`(obj, manager)

  Bases: `sqlalchemy.orm.base.InspectionAttr`

  tracks state information at the instance level.

  The `InstanceState` is a key object used by the SQLAlchemy ORM in order to track the state of an object; it is created the moment an object is instantiated, typically as a result of instrumentation which SQLAlchemy applies to the `__init__()` method of the class.

  `InstanceState` is also a semi-public object, available for runtime inspection as to the state of a mapped instance, including information such as its current status within a particular `Session` and details about data on individual attributes. The public API in order to acquire a `InstanceState` object is to use the `inspect()` system:

      >>> from sqlalchemy import inspect
      >>> insp = inspect(some_mapped_object)

  See also

  Runtime Inspection API

  `attrs`

    Return a namespace representing each attribute on the mapped object, including its current value and history.

    The returned object is an instance of `AttributeState`. This object allows inspection of the current data within an attribute as well as attribute history since the last flush.

  `callables` = ()

    A namespace where a per-state loader callable can be associated.

    In SQLAlchemy 1.0, this is only used for lazy loaders / deferred loaders that were set up via query option.

    Previously, callables was used also to indicate expired attributes by storing a link to the InstanceState itself in this dictionary. This role is now handled by the expired_attributes set.

  `deleted`

    Return true if the object is deleted.

    An object that is in the deleted state is guaranteed to not be within the `Session.identity_map` of its parent `Session`; however if the session’s transaction is rolled back, the object will be restored to the persistent state and the identity map.

    Note

    The `InstanceState.deleted` attribute refers to a specific state of the object that occurs between the “persistent” and “detached” states; once the object is detached, the `InstanceState.deleted` attribute no longer returns True; in order to detect that a state was deleted, regardless of whether or not the object is associated with a `Session`, use the `InstanceState.was_deleted` accessor.

    See also

    Quickie Intro to Object States

  `detached`

    Return true if the object is detached.

    See also

    Quickie Intro to Object States

  `dict`

    Return the instance dict used by the object.

    Under normal circumstances, this is always synonymous with the `__dict__` attribute of the mapped object, unless an alternative instrumentation system has been configured.

    In the case that the actual object has been garbage collected, this accessor returns a blank dictionary.

  `expired_attributes` = None

    The set of keys which are ‘expired’ to be loaded by the manager’s deferred scalar loader, assuming no pending changes.

    see also the `unmodified` collection which is intersected against this set when a refresh operation occurs.

  `has_identity`

    Return `True` if this object has an identity key.

    This should always have the same value as the expression `state.persistent or state.detached`.

  `identity`

    Return the mapped identity of the mapped object. This is the primary key identity as persisted by the ORM which can always be passed directly to `Query.get()`.

    Returns `None` if the object has no primary key identity.

    Note

    An object which is transient or pending does not have a mapped identity until it is flushed, even if its attributes include primary key values.

  `identity_key`

    Return the identity key for the mapped object.

    This is the key used to locate the object within the `Session.identity_map` mapping. It contains the identity as returned by `identity` within it.

  `mapper`

    Return the `Mapper` used for this mapepd object.

  `object`

    Return the mapped object represented by this `InstanceState`.

  `pending`

    Return true if the object is pending.

    See also

    Quickie Intro to Object States

  `persistent`

    Return true if the object is persistent.

    An object that is in the persistent state is guaranteed to be within the `Session.identity_map` of its parent `Session`.

    Changed in version 1.1: The `InstanceState.persistent` accessor no longer returns True for an object that was “deleted” within a flush; use the `InstanceState.deleted` accessor to detect this state. This allows the “persistent” state to guarantee membership in the identity map.

    See also

    Quickie Intro to Object States

  `session`

    Return the owning `Session` for this instance, or `None` if none available.

    Note that the result here can in some cases be different from that of `obj in session`; an object that’s been deleted will report as not `in session`, however if the transaction is still in progress, this attribute will still refer to that session. Only when the transaction is completed does the object become fully detached under normal circumstances.

  `transient`

    Return true if the object is transient.

    See also

    Quickie Intro to Object States

  `unloaded`

    Return the set of keys which do not have a loaded value.

    This includes expired attributes and any other attribute that was never populated or modified.

  `unloaded_expirable`

    Return the set of keys which do not have a loaded value.

    This includes expired attributes and any other attribute that was never populated or modified.

  `unmodified`

    Return the set of keys which have no uncommitted changes

  `unmodified_intersection`(keys)

    Return self.unmodified.intersection(keys).

  `was_deleted`

    Return True if this object is or was previously in the “deleted” state and has not been reverted to persistent.

    This flag returns True once the object was deleted in flush. When the object is expunged from the session either explicitly or via transaction commit and enters the “detached” state, this flag will continue to report True.

    New in version 1.1: - added a local method form of `orm.util.was_deleted()`.

    See also

    `InstanceState.deleted` - refers to the “deleted” state

    `orm.util.was_deleted()` - standalone function

    Quickie Intro to Object States

class `sqlalchemy.orm.attributes.` `InstrumentedAttribute`(class_, key, impl=None, comparator=None, parententity=None, of_type=None)

  Bases: `sqlalchemy.orm.attributes.QueryableAttribute`

  Class bound instrumented attribute which adds basic descriptor methods.

  See `QueryableAttribute` for a description of most features.

  `__delete__`(instance)
  `__get__`(instance, owner)
  `__set__`(instance, value)

`sqlalchemy.orm.interfaces.` `MANYTOONE` = symbol('MANYTOONE')

  Indicates the many-to-one direction for a `relationship()`.

  This symbol is typically used by the internals but may be exposed within certain API features.

`sqlalchemy.orm.interfaces.` `MANYTOMANY` = symbol('MANYTOMANY')

  Indicates the many-to-many direction for a `relationship()`.

  This symbol is typically used by the internals but may be exposed within certain API features.

class `sqlalchemy.orm.interfaces.` `MapperProperty`

  Bases: `sqlalchemy.orm.base._MappedAttribute`, `sqlalchemy.orm.base.InspectionAttr`, `sqlalchemy.util.langhelpers.MemoizedSlots`

  Represent a particular class attribute mapped by `Mapper`.

  The most common occurrences of `MapperProperty` are the mapped `Column`, which is represented in a mapping as an instance of `ColumnProperty`, and a reference to another class produced by `relationship()`, represented in the mapping as an instance of `RelationshipProperty`.

  `info`

    Info dictionary associated with the object, allowing user-defined data to be associated with this `InspectionAttr`.

    The dictionary is generated when first accessed. Alternatively, it can be specified as a constructor argument to the `column_property()`, `relationship()`, or `composite()` functions.

    New in version 0.8: Added support for .info to all `MapperProperty` subclasses.

    Changed in version 1.0.0: `InspectionAttr.info` moved from `MapperProperty` so that it can apply to a wider variety of ORM and extension constructs.

    See also

    `QueryableAttribute.info`

    `SchemaItem.info`

  `cascade` = frozenset()

    The set of ‘cascade’ attribute names.

    This collection is checked before the ‘cascade_iterator’ method is called.

    The collection typically only applies to a RelationshipProperty.

  `cascade_iterator`(type_, state, visited_instances=None, halt_on=None)

    Iterate through instances related to the given instance for a particular ‘cascade’, starting with this MapperProperty.

    Return an iterator3-tuples (instance, mapper, state).

    Note that the ‘cascade’ collection on this MapperProperty is checked first for the given type before cascade_iterator is called.

    This method typically only applies to RelationshipProperty.

  `class_attribute`

    Return the class-bound descriptor corresponding to this `MapperProperty`.

    This is basically a `getattr()` call:

        return getattr(self.parent.class_, self.key)

    I.e. if this `MapperProperty` were named `addresses`, and the class to which it is mapped is `User`, this sequence is possible:

        >>> from sqlalchemy import inspect
        >>> mapper = inspect(User)
        >>> addresses_property = mapper.attrs.addresses
        >>> addresses_property.class_attribute is User.addresses
        True
        >>> User.addresses.property is addresses_property
        True

  `create_row_processor`(context, path, mapper, result, adapter, populators)

    Produce row processing functions and append to the given set of populators lists.

  `do_init`()

    Perform subclass-specific initialization post-mapper-creation steps.

    This is a template method called by the `MapperProperty` object’s init() method.

  `init`()

    Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.

  `instrument_class`(mapper)

    Hook called by the Mapper to the property to initiate instrumentation of the class attribute managed by this MapperProperty.

    The MapperProperty here will typically call out to the attributes module to set up an InstrumentedAttribute.

    This step is the first of two steps to set up an InstrumentedAttribute, and is called early in the mapper setup process.

    The second step is typically the init_class_attribute step, called from StrategizedProperty via the post_instrument_class() hook. This step assigns additional state to the InstrumentedAttribute (specifically the “impl”) which has been determined after the MapperProperty has determined what kind of persistence management it needs to do (e.g. scalar, object, collection, etc).

  `is_property` = True

    Part of the InspectionAttr interface; states this object is a mapper property.

  `merge`(session, source_state, source_dict, dest_state, dest_dict, load, _recursive, _resolve_conflict_map)

    Merge the attribute represented by this `MapperProperty` from source to destination object.

  `post_instrument_class`(mapper)

    Perform instrumentation adjustments that need to occur after init() has completed.

    The given Mapper is the Mapper invoking the operation, which may not be the same Mapper as self.parent in an inheritance scenario; however, Mapper will always at least be a sub-mapper of self.parent.

    This method is typically used by StrategizedProperty, which delegates it to LoaderStrategy.init_class_attribute() to perform final setup on the class-bound InstrumentedAttribute.

  `set_parent`(parent, init)

    Set the parent mapper that references this MapperProperty.

    This method is overridden by some subclasses to perform extra setup when the mapper is first known.

  `setup`(context, entity, path, adapter, **kwargs)

    Called by Query for the purposes of constructing a SQL statement.

    Each MapperProperty associated with the target mapper processes the statement referenced by the query context, adding columns and/or criterion as appropriate.

`sqlalchemy.orm.interfaces.` `NOT_EXTENSION` = symbol('NOT_EXTENSION')

  Symbol indicating an `InspectionAttr` that’s not part of sqlalchemy.ext.

  Is assigned to the `InspectionAttr.extension_type` attibute.

`sqlalchemy.orm.interfaces.` `ONETOMANY` = symbol('ONETOMANY')

  Indicates the one-to-many direction for a `relationship()`.

  This symbol is typically used by the internals but may be exposed within certain API features.

class `sqlalchemy.orm.interfaces.` `PropComparator`(prop, parentmapper, adapt_to_entity=None)

  Bases: `sqlalchemy.sql.operators.ColumnOperators`

  Defines SQL operators for `MapperProperty` objects.

  SQLAlchemy allows for operators to be redefined at both the Core and ORM level. `PropComparator` is the base class of operator redefinition for ORM-level operations, including those of `ColumnProperty`, `RelationshipProperty`, and `CompositeProperty`.

  Note

  With the advent of Hybrid properties introduced in SQLAlchemy 0.7, as well as Core-level operator redefinition in SQLAlchemy 0.8, the use case for user-defined `PropComparator` instances is extremely rare. See Hybrid Attributes as well as Redefining and Creating New Operators.

  User-defined subclasses of `PropComparator` may be created. The built-in Python comparison and math operator methods, such as `operators.ColumnOperators.__eq__()`, `operators.ColumnOperators.__lt__()`, and `operators.ColumnOperators.__add__()`, can be overridden to provide new operator behavior. The custom `PropComparator` is passed to the `MapperProperty` instance via the `comparator_factory` argument. In each case, the appropriate subclass of `PropComparator` should be used:

      # definition of custom PropComparator subclasses

      from sqlalchemy.orm.properties import \
                              ColumnProperty,\
                              CompositeProperty,\
                              RelationshipProperty

      class MyColumnComparator(ColumnProperty.Comparator):
          def __eq__(self, other):
              return self.__clause_element__() == other

      class MyRelationshipComparator(RelationshipProperty.Comparator):
          def any(self, expression):
              "define the 'any' operation"
              # ...

      class MyCompositeComparator(CompositeProperty.Comparator):
          def __gt__(self, other):
              "redefine the 'greater than' operation"

              return sql.and_(*[a>b for a, b in
                                zip(self.__clause_element__().clauses,
                                    other.__composite_values__())])

      # application of custom PropComparator subclasses

      from sqlalchemy.orm import column_property, relationship, composite
      from sqlalchemy import Column, String

      class SomeMappedClass(Base):
          some_column = column_property(Column("some_column", String),
                              comparator_factory=MyColumnComparator)

          some_relationship = relationship(SomeOtherClass,
                              comparator_factory=MyRelationshipComparator)

          some_composite = composite(
                  Column("a", String), Column("b", String),
                  comparator_factory=MyCompositeComparator
              )

  Note that for column-level operator redefinition, it’s usually simpler to define the operators at the Core level, using the `TypeEngine.comparator_factory` attribute. See Redefining and Creating New Operators for more detail.

  See also:

  `ColumnProperty.Comparator`

  `RelationshipProperty.Comparator`

  `CompositeProperty.Comparator`

  `ColumnOperators`

  Redefining and Creating New Operators

  `TypeEngine.comparator_factory`

  `__eq__`(other)
    inherited from the `__eq__()` method of `ColumnOperators`

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  `__le__`(other)
    inherited from the `__le__()` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  `__lt__`(other)
    inherited from the `__lt__()` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  `__ne__`(other)
    inherited from the `__ne__()` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  `adapt_to_entity`(adapt_to_entity)

    Return a copy of this PropComparator which will use the given `AliasedInsp` to produce corresponding expressions.

  `adapter`

    Produce a callable that adapts column expressions to suit an aliased version of this comparator.

  `all_`()
    inherited from the `all_()` method of `ColumnOperators`

    Produce a `all_()` clause against the parent object.

    This operator is only appropriate against a scalar subquery object, or for some backends an column expression that is against the ARRAY type, e.g.:

        # postgresql '5 = ALL (somearray)'
        expr = 5 == mytable.c.somearray.all_()

        # mysql '5 = ALL (SELECT value FROM table)'
        expr = 5 == select([table.c.value]).as_scalar().all_()

    See also

    `all_()` - standalone version

    `any_()` - ANY operator

    New in version 1.1.

  `any`(criterion=None, **kwargs)

    Return true if this collection contains any member that meets the given criterion.

    The usual implementation of `any()` is `RelationshipProperty.Comparator.any()`.

    Parameters: | criterion – an optional ClauseElement formulated against the member class’ table or attributes. **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.

  `any_`()
    inherited from the `any_()` method of `ColumnOperators`

    Produce a `any_()` clause against the parent object.

    This operator is only appropriate against a scalar subquery object, or for some backends an column expression that is against the ARRAY type, e.g.:

        # postgresql '5 = ANY (somearray)'
        expr = 5 == mytable.c.somearray.any_()

        # mysql '5 = ANY (SELECT value FROM table)'
        expr = 5 == select([table.c.value]).as_scalar().any_()

    See also

    `any_()` - standalone version

    `all_()` - ALL operator

    New in version 1.1.

  `asc`()
    inherited from the `asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  `between`(cleft, cright, symmetric=False)
    inherited from the `between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  `bool_op`(opstring, precedence=0)
    inherited from the `bool_op()` method of `Operators`

    Return a custom boolean operator.

    This method is shorthand for calling `Operators.op()` and passing the `Operators.op.is_comparison` flag with True.

    New in version 1.2.0b3.

    See also

    `Operators.op()`

  `collate`(collation)
    inherited from the `collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

    See also

    `collate()`

  `concat`(other)
    inherited from the `concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  `contains`(other, **kwargs)
    inherited from the `contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    Produces a LIKE expression that tests against a match for the middle of a string value:

        column LIKE '%' || <other> || '%'

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.contains("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.contains.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.contains.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.contains.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
          somecolumn.contains("foo%bar", autoescape=True)
      Will render as:
          somecolumn LIKE '%' || :param || '%' ESCAPE '/'
    - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.contains.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.contains.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
          somecolumn.contains("foo/%bar", escape="^")
      Will render as:
          somecolumn LIKE '%' || :param || '%' ESCAPE '^'
      The parameter may also be combined with `ColumnOperators.contains.autoescape`:
          somecolumn.contains("foo%bar^bat", escape="^", autoescape=True)
    Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

    `ColumnOperators.endswith()`

    `ColumnOperators.like()`

  `desc`()
    inherited from the `desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  `distinct`()
    inherited from the `distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  `endswith`(other, **kwargs)
    inherited from the `endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    Produces a LIKE expression that tests against a match for the end of a string value:

        column LIKE '%' || <other>

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.endswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.endswith.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.endswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.endswith.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
          somecolumn.endswith("foo%bar", autoescape=True)
      Will render as:
          somecolumn LIKE '%' || :param ESCAPE '/'
    - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.endswith.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.endswith.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
          somecolumn.endswith("foo/%bar", escape="^")
      Will render as:
          somecolumn LIKE '%' || :param ESCAPE '^'
      The parameter may also be combined with `ColumnOperators.endswith.autoescape`:
          somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)
    Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

  `has`(criterion=None, **kwargs)

    Return true if this element references a member which meets the given criterion.

    The usual implementation of `has()` is `RelationshipProperty.Comparator.has()`.

    Parameters: | criterion – an optional ClauseElement formulated against the member class’ table or attributes. **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.

  `ilike`(other, escape=None)
    inherited from the `ilike()` method of `ColumnOperators`

    Implement the `ilike` operator, e.g. case insensitive LIKE.

    In a column context, produces an expression either of the form:

        lower(a) LIKE lower(other)

    Or on backends that support the ILIKE operator:

        a ILIKE other

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.ilike("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  `in_`(other)
    inherited from the `in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

    In the case that `other` is an empty sequence, the compiler produces an “empty in” expression. This defaults to the expression “1 != 1” to produce false in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.notin_()` operators now produce a “static” expression for an empty IN sequence by default.

  `is_`(other)
    inherited from the `is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.isnot()`

  `is_distinct_from`(other)
    inherited from the `is_distinct_from()` method of `ColumnOperators`

    Implement the `IS DISTINCT FROM` operator.

    Renders “a IS DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS NOT b”.

    New in version 1.1.

  `isnot`(other)
    inherited from the `isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.is_()`

  `isnot_distinct_from`(other)
    inherited from the `isnot_distinct_from()` method of `ColumnOperators`

    Implement the `IS NOT DISTINCT FROM` operator.

    Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

    New in version 1.1.

  `like`(other, escape=None)
    inherited from the `like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the expression:

        a LIKE other

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.like("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  `match`(other, **kwargs)
    inherited from the `match()` method of `ColumnOperators`

    Implements a database-specific ‘match’ operator.

    `match()` attempts to resolve to a MATCH-like function or operator provided by the backend. Examples include:

    - PostgreSQL - renders `x @@ to_tsquery(y)`
    - MySQL - renders `MATCH (x) AGAINST (y IN BOOLEAN MODE)`
    - Oracle - renders `CONTAINS(x, y)`
    - other backends may provide special implementations.
    - Backends without any special implementation will emit the operator as “MATCH”. This is compatible with SQlite, for example.
  `notilike`(other, escape=None)
    inherited from the `notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.ilike()`

  `notin_`(other)
    inherited from the `notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.notin_()` operators now produce a “static” expression for an empty IN sequence by default.

    See also

    `ColumnOperators.in_()`

  `notlike`(other, escape=None)
    inherited from the `notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.like()`

  `nullsfirst`()
    inherited from the `nullsfirst()` method of `ColumnOperators`

    Produce a `nullsfirst()` clause against the parent object.

  `nullslast`()
    inherited from the `nullslast()` method of `ColumnOperators`

    Produce a `nullslast()` clause against the parent object.

  `of_type`(class_)

    Redefine this object in terms of a polymorphic subclass.

    Returns a new PropComparator from which further criterion can be evaluated.

    e.g.:

        query.join(Company.employees.of_type(Engineer)).\
           filter(Engineer.name=='foo')

    Parameters: | class_ – a class or mapper indicating that criterion will be against this specific subclass.

    See also

    Referring to specific subtypes on relationships

  `op`(opstring, precedence=0, is_comparison=False, return_type=None)
    inherited from the `op()` method of `Operators`

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument. is_comparison – if True, the operator will be considered as a “comparison” operator, that is which evaluates to a boolean true/false value, like `==`, `>`, etc. This flag should be set so that ORM relationships can establish that the operator is a comparison operator when used in a custom join condition. New in version 0.9.2: - added the `Operators.op.is_comparison` flag. return_type – a `TypeEngine` class or object that will force the return type of an expression produced by this operator to be of that type. By default, operators that specify `Operators.op.is_comparison` will resolve to `Boolean`, and those that do not will be of the same type as the left-hand operand. New in version 1.2.0b3: - added the `Operators.op.return_type` argument.

    See also

    Redefining and Creating New Operators

    Using custom operators in join conditions

  `operate`(op, *other, **kwargs)
    inherited from the `operate()` method of `Operators`

    Operate on an argument.

    This is the lowest level of operation, raises `NotImplementedError` by default.

    Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding `ColumnOperators` to apply `func.lower()` to the left and right side:

        class MyComparator(ColumnOperators):
            def operate(self, op, other):
                return op(func.lower(self), func.lower(other))

    Parameters: | op – Operator callable. *other – the ‘other’ side of the operation. Will be a single scalar for most operations. **kwargs – modifiers. These may be passed by special operators such as `ColumnOperators.contains()`.

  `reverse_operate`(op, other, **kwargs)
    inherited from the `reverse_operate()` method of `Operators`

    Reverse operate on an argument.

    Usage is the same as `operate()`.

  `startswith`(other, **kwargs)
    inherited from the `startswith()` method of `ColumnOperators`

    Implement the `startswith` operator.

    Produces a LIKE expression that tests against a match for the start of a string value:

        column LIKE <other> || '%'

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.startswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.startswith.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.startswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.startswith.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
          somecolumn.startswith("foo%bar", autoescape=True)
      Will render as:
          somecolumn LIKE :param || '%' ESCAPE '/'
    - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.startswith.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.startswith.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
          somecolumn.startswith("foo/%bar", escape="^")
      Will render as:
          somecolumn LIKE :param || '%' ESCAPE '^'
      The parameter may also be combined with `ColumnOperators.startswith.autoescape`:
          somecolumn.startswith("foo%bar^bat", escape="^", autoescape=True)
    Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.endswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

class `sqlalchemy.orm.properties.` `RelationshipProperty`(argument, secondary=None, primaryjoin=None, secondaryjoin=None, foreign_keys=None, uselist=None, order_by=False, backref=None, back_populates=None, post_update=False, cascade=False, extension=None, viewonly=False, lazy='select', collection_class=None, passive_deletes=False, passive_updates=True, remote_side=None, enable_typechecks=True, join_depth=None, comparator_factory=None, single_parent=False, innerjoin=False, distinct_target_key=None, doc=None, active_history=False, cascade_backrefs=True, load_on_pending=False, bake_queries=True, _local_remote_pairs=None, query_class=None, info=None)

  Bases: `sqlalchemy.orm.interfaces.StrategizedProperty`

  Describes an object property that holds a single item or list of items that correspond to a related database table.

  Public constructor is the `orm.relationship()` function.

  See also:

  Relationship Configuration

  class `Comparator`(prop, parentmapper, adapt_to_entity=None, of_type=None)

    Bases: `sqlalchemy.orm.interfaces.PropComparator`

    Produce boolean, comparison, and other operators for `RelationshipProperty` attributes.

    See the documentation for `PropComparator` for a brief overview of ORM level operator definition.

    See also:

    `PropComparator`

    `ColumnProperty.Comparator`

    `ColumnOperators`

    Redefining and Creating New Operators

    `TypeEngine.comparator_factory`

    `__eq__`(other)

      Implement the `==` operator.

      In a many-to-one context, such as:

          MyClass.some_prop == <some object>

      this will typically produce a clause such as:

          mytable.related_id == <some id>

      Where `<some id>` is the primary key of the given object.

      The `==` operator provides partial functionality for non- many-to-one comparisons:

      - Comparisons against collections are not supported. Use `contains()`.
      - Compared to a scalar one-to-many, will produce a clause that compares the target columns in the parent to the given target.
      - Compared to a scalar many-to-many, an alias of the association table will be rendered as well, forming a natural join that is part of the main body of the query. This will not work for queries that go beyond simple AND conjunctions of comparisons, such as those which use OR. Use explicit joins, outerjoins, or `has()` for more comprehensive non-many-to-one scalar membership tests.
      - Comparisons against `None` given in a one-to-many or many-to-many context produce a NOT EXISTS clause.
    `__init__`(prop, parentmapper, adapt_to_entity=None, of_type=None)

      Construction of `RelationshipProperty.Comparator` is internal to the ORM’s attribute mechanics.

    `__le__`(other)
      inherited from the `__le__()` method of `ColumnOperators`

      Implement the `<=` operator.

      In a column context, produces the clause `a <= b`.

    `__lt__`(other)
      inherited from the `__lt__()` method of `ColumnOperators`

      Implement the `<` operator.

      In a column context, produces the clause `a < b`.

    `__ne__`(other)

      Implement the `!=` operator.

      In a many-to-one context, such as:

          MyClass.some_prop != <some object>

      This will typically produce a clause such as:

          mytable.related_id != <some id>

      Where `<some id>` is the primary key of the given object.

      The `!=` operator provides partial functionality for non- many-to-one comparisons:

      - Comparisons against collections are not supported. Use `contains()` in conjunction with `not_()`.
      - Compared to a scalar one-to-many, will produce a clause that compares the target columns in the parent to the given target.
      - Compared to a scalar many-to-many, an alias of the association table will be rendered as well, forming a natural join that is part of the main body of the query. This will not work for queries that go beyond simple AND conjunctions of comparisons, such as those which use OR. Use explicit joins, outerjoins, or `has()` in conjunction with `not_()` for more comprehensive non-many-to-one scalar membership tests.
      - Comparisons against `None` given in a one-to-many or many-to-many context produce an EXISTS clause.
    `adapt_to_entity`(adapt_to_entity)

      Return a copy of this PropComparator which will use the given `AliasedInsp` to produce corresponding expressions.

    `adapter`
      inherited from the `adapter` attribute of `PropComparator`

      Produce a callable that adapts column expressions to suit an aliased version of this comparator.

    `all_`()
      inherited from the `all_()` method of `ColumnOperators`

      Produce a `all_()` clause against the parent object.

      This operator is only appropriate against a scalar subquery object, or for some backends an column expression that is against the ARRAY type, e.g.:

          # postgresql '5 = ALL (somearray)'
          expr = 5 == mytable.c.somearray.all_()

          # mysql '5 = ALL (SELECT value FROM table)'
          expr = 5 == select([table.c.value]).as_scalar().all_()

      See also

      `all_()` - standalone version

      `any_()` - ANY operator

      New in version 1.1.

    `any`(criterion=None, **kwargs)

      Produce an expression that tests a collection against particular criterion, using EXISTS.

      An expression like:

          session.query(MyClass).filter(
              MyClass.somereference.any(SomeRelated.x==2)
          )

      Will produce a query like:

          SELECT * FROM my_table WHERE
          EXISTS (SELECT 1 FROM related WHERE related.my_id=my_table.id
          AND related.x=2)

      Because `any()` uses a correlated subquery, its performance is not nearly as good when compared against large target tables as that of using a join.

      `any()` is particularly useful for testing for empty collections:

          session.query(MyClass).filter(
              ~MyClass.somereference.any()
          )

      will produce:

          SELECT * FROM my_table WHERE
          NOT EXISTS (SELECT 1 FROM related WHERE
          related.my_id=my_table.id)

      `any()` is only valid for collections, i.e. a `relationship()` that has `uselist=True`. For scalar references, use `has()`.

    `any_`()
      inherited from the `any_()` method of `ColumnOperators`

      Produce a `any_()` clause against the parent object.

      This operator is only appropriate against a scalar subquery object, or for some backends an column expression that is against the ARRAY type, e.g.:

          # postgresql '5 = ANY (somearray)'
          expr = 5 == mytable.c.somearray.any_()

          # mysql '5 = ANY (SELECT value FROM table)'
          expr = 5 == select([table.c.value]).as_scalar().any_()

      See also

      `any_()` - standalone version

      `all_()` - ALL operator

      New in version 1.1.

    `asc`()
      inherited from the `asc()` method of `ColumnOperators`

      Produce a `asc()` clause against the parent object.

    `between`(cleft, cright, symmetric=False)
      inherited from the `between()` method of `ColumnOperators`

      Produce a `between()` clause against the parent object, given the lower and upper range.

    `bool_op`(opstring, precedence=0)
      inherited from the `bool_op()` method of `Operators`

      Return a custom boolean operator.

      This method is shorthand for calling `Operators.op()` and passing the `Operators.op.is_comparison` flag with True.

      New in version 1.2.0b3.

      See also

      `Operators.op()`

    `collate`(collation)
      inherited from the `collate()` method of `ColumnOperators`

      Produce a `collate()` clause against the parent object, given the collation string.

      See also

      `collate()`

    `concat`(other)
      inherited from the `concat()` method of `ColumnOperators`

      Implement the ‘concat’ operator.

      In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

    `contains`(other, **kwargs)

      Return a simple expression that tests a collection for containment of a particular item.

      `contains()` is only valid for a collection, i.e. a `relationship()` that implements one-to-many or many-to-many with `uselist=True`.

      When used in a simple one-to-many context, an expression like:

          MyClass.contains(other)

      Produces a clause like:

          mytable.id == <some id>

      Where `<some id>` is the value of the foreign key attribute on `other` which refers to the primary key of its parent object. From this it follows that `contains()` is very useful when used with simple one-to-many operations.

      For many-to-many operations, the behavior of `contains()` has more caveats. The association table will be rendered in the statement, producing an “implicit” join, that is, includes multiple tables in the FROM clause which are equated in the WHERE clause:

          query(MyClass).filter(MyClass.contains(other))

      Produces a query like:

          SELECT * FROM my_table, my_association_table AS
          my_association_table_1 WHERE
          my_table.id = my_association_table_1.parent_id
          AND my_association_table_1.child_id = <some id>

      Where `<some id>` would be the primary key of `other`. From the above, it is clear that `contains()` will not work with many-to-many collections when used in queries that move beyond simple AND conjunctions, such as multiple `contains()` expressions joined by OR. In such cases subqueries or explicit “outer joins” will need to be used instead. See `any()` for a less-performant alternative using EXISTS, or refer to `Query.outerjoin()` as well as Querying with Joins for more details on constructing outer joins.

    `desc`()
      inherited from the `desc()` method of `ColumnOperators`

      Produce a `desc()` clause against the parent object.

    `distinct`()
      inherited from the `distinct()` method of `ColumnOperators`

      Produce a `distinct()` clause against the parent object.

    `endswith`(other, **kwargs)
      inherited from the `endswith()` method of `ColumnOperators`

      Implement the ‘endswith’ operator.

      Produces a LIKE expression that tests against a match for the end of a string value:

          column LIKE '%' || <other>

      E.g.:

          stmt = select([sometable]).\
              where(sometable.c.column.endswith("foobar"))

      Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.endswith.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.endswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

      - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.endswith.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
            somecolumn.endswith("foo%bar", autoescape=True)
        Will render as:
            somecolumn LIKE '%' || :param ESCAPE '/'
      - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.endswith.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.endswith.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
            somecolumn.endswith("foo/%bar", escape="^")
        Will render as:
            somecolumn LIKE '%' || :param ESCAPE '^'
        The parameter may also be combined with `ColumnOperators.endswith.autoescape`:
            somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)
      Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

      See also

      `ColumnOperators.startswith()`

      `ColumnOperators.contains()`

      `ColumnOperators.like()`

    `has`(criterion=None, **kwargs)

      Produce an expression that tests a scalar reference against particular criterion, using EXISTS.

      An expression like:

          session.query(MyClass).filter(
              MyClass.somereference.has(SomeRelated.x==2)
          )

      Will produce a query like:

          SELECT * FROM my_table WHERE
          EXISTS (SELECT 1 FROM related WHERE
          related.id==my_table.related_id AND related.x=2)

      Because `has()` uses a correlated subquery, its performance is not nearly as good when compared against large target tables as that of using a join.

      `has()` is only valid for scalar references, i.e. a `relationship()` that has `uselist=False`. For collection references, use `any()`.

    `ilike`(other, escape=None)
      inherited from the `ilike()` method of `ColumnOperators`

      Implement the `ilike` operator, e.g. case insensitive LIKE.

      In a column context, produces an expression either of the form:

          lower(a) LIKE lower(other)

      Or on backends that support the ILIKE operator:

          a ILIKE other

      E.g.:

          stmt = select([sometable]).\
              where(sometable.c.column.ilike("%foobar%"))

      - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
            somecolumn.ilike("foo/%bar", escape="/")

      See also

      `ColumnOperators.like()`

    `in_`(other)

      Produce an IN clause - this is not implemented for `relationship()`-based attributes at this time.

    `is_`(other)
      inherited from the `is_()` method of `ColumnOperators`

      Implement the `IS` operator.

      Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

      New in version 0.7.9.

      See also

      `ColumnOperators.isnot()`

    `is_distinct_from`(other)
      inherited from the `is_distinct_from()` method of `ColumnOperators`

      Implement the `IS DISTINCT FROM` operator.

      Renders “a IS DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS NOT b”.

      New in version 1.1.

    `isnot`(other)
      inherited from the `isnot()` method of `ColumnOperators`

      Implement the `IS NOT` operator.

      Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

      New in version 0.7.9.

      See also

      `ColumnOperators.is_()`

    `isnot_distinct_from`(other)
      inherited from the `isnot_distinct_from()` method of `ColumnOperators`

      Implement the `IS NOT DISTINCT FROM` operator.

      Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

      New in version 1.1.

    `like`(other, escape=None)
      inherited from the `like()` method of `ColumnOperators`

      Implement the `like` operator.

      In a column context, produces the expression:

          a LIKE other

      E.g.:

          stmt = select([sometable]).\
              where(sometable.c.column.like("%foobar%"))

      - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
            somecolumn.like("foo/%bar", escape="/")

      See also

      `ColumnOperators.ilike()`

    `mapper`

      The target `Mapper` referred to by this `RelationshipProperty.Comparator`.

      This is the “target” or “remote” side of the `relationship()`.

    `match`(other, **kwargs)
      inherited from the `match()` method of `ColumnOperators`

      Implements a database-specific ‘match’ operator.

      `match()` attempts to resolve to a MATCH-like function or operator provided by the backend. Examples include:

      - PostgreSQL - renders `x @@ to_tsquery(y)`
      - MySQL - renders `MATCH (x) AGAINST (y IN BOOLEAN MODE)`
      - Oracle - renders `CONTAINS(x, y)`
      - other backends may provide special implementations.
      - Backends without any special implementation will emit the operator as “MATCH”. This is compatible with SQlite, for example.
    `notilike`(other, escape=None)
      inherited from the `notilike()` method of `ColumnOperators`

      implement the `NOT ILIKE` operator.

      This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

      New in version 0.8.

      See also

      `ColumnOperators.ilike()`

    `notin_`(other)
      inherited from the `notin_()` method of `ColumnOperators`

      implement the `NOT IN` operator.

      This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

      In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

      Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.notin_()` operators now produce a “static” expression for an empty IN sequence by default.

      See also

      `ColumnOperators.in_()`

    `notlike`(other, escape=None)
      inherited from the `notlike()` method of `ColumnOperators`

      implement the `NOT LIKE` operator.

      This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

      New in version 0.8.

      See also

      `ColumnOperators.like()`

    `nullsfirst`()
      inherited from the `nullsfirst()` method of `ColumnOperators`

      Produce a `nullsfirst()` clause against the parent object.

    `nullslast`()
      inherited from the `nullslast()` method of `ColumnOperators`

      Produce a `nullslast()` clause against the parent object.

    `of_type`(cls)

      Redefine this object in terms of a polymorphic subclass.

      See `PropComparator.of_type()` for an example.

    `op`(opstring, precedence=0, is_comparison=False, return_type=None)
      inherited from the `op()` method of `Operators`

      produce a generic operator function.

      e.g.:

          somecolumn.op("*")(5)

      produces:

          somecolumn * 5

      This function can also be used to make bitwise operators explicit. For example:

          somecolumn.op('&')(0xff)

      is a bitwise AND of the value in `somecolumn`.

      Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument. is_comparison – if True, the operator will be considered as a “comparison” operator, that is which evaluates to a boolean true/false value, like `==`, `>`, etc. This flag should be set so that ORM relationships can establish that the operator is a comparison operator when used in a custom join condition. New in version 0.9.2: - added the `Operators.op.is_comparison` flag. return_type – a `TypeEngine` class or object that will force the return type of an expression produced by this operator to be of that type. By default, operators that specify `Operators.op.is_comparison` will resolve to `Boolean`, and those that do not will be of the same type as the left-hand operand. New in version 1.2.0b3: - added the `Operators.op.return_type` argument.

      See also

      Redefining and Creating New Operators

      Using custom operators in join conditions

    `operate`(op, *other, **kwargs)
      inherited from the `operate()` method of `Operators`

      Operate on an argument.

      This is the lowest level of operation, raises `NotImplementedError` by default.

      Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding `ColumnOperators` to apply `func.lower()` to the left and right side:

          class MyComparator(ColumnOperators):
              def operate(self, op, other):
                  return op(func.lower(self), func.lower(other))

      Parameters: | op – Operator callable. *other – the ‘other’ side of the operation. Will be a single scalar for most operations. **kwargs – modifiers. These may be passed by special operators such as `ColumnOperators.contains()`.

    `reverse_operate`(op, other, **kwargs)
      inherited from the `reverse_operate()` method of `Operators`

      Reverse operate on an argument.

      Usage is the same as `operate()`.

    `startswith`(other, **kwargs)
      inherited from the `startswith()` method of `ColumnOperators`

      Implement the `startswith` operator.

      Produces a LIKE expression that tests against a match for the start of a string value:

          column LIKE <other> || '%'

      E.g.:

          stmt = select([sometable]).\
              where(sometable.c.column.startswith("foobar"))

      Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.startswith.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.startswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

      - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.startswith.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
            somecolumn.startswith("foo%bar", autoescape=True)
        Will render as:
            somecolumn LIKE :param || '%' ESCAPE '/'
      - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.startswith.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.startswith.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
            somecolumn.startswith("foo/%bar", escape="^")
        Will render as:
            somecolumn LIKE :param || '%' ESCAPE '^'
        The parameter may also be combined with `ColumnOperators.startswith.autoescape`:
            somecolumn.startswith("foo%bar^bat", escape="^", autoescape=True)
      Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

      See also

      `ColumnOperators.endswith()`

      `ColumnOperators.contains()`

      `ColumnOperators.like()`

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__init__`(argument, secondary=None, primaryjoin=None, secondaryjoin=None, foreign_keys=None, uselist=None, order_by=False, backref=None, back_populates=None, post_update=False, cascade=False, extension=None, viewonly=False, lazy='select', collection_class=None, passive_deletes=False, passive_updates=True, remote_side=None, enable_typechecks=True, join_depth=None, comparator_factory=None, single_parent=False, innerjoin=False, distinct_target_key=None, doc=None, active_history=False, cascade_backrefs=True, load_on_pending=False, bake_queries=True, _local_remote_pairs=None, query_class=None, info=None)

    Construct a new `RelationshipProperty` object.

    This constructor is mirrored as a public API function; see `relationship()` for a full usage and argument description.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `cascade`

    Return the current cascade setting for this `RelationshipProperty`.

  `cascade_iterator`(type_, state, dict_, visited_states, halt_on=None)

    Iterate through instances related to the given instance for a particular ‘cascade’, starting with this MapperProperty.

    Return an iterator3-tuples (instance, mapper, state).

    Note that the ‘cascade’ collection on this MapperProperty is checked first for the given type before cascade_iterator is called.

    This method typically only applies to RelationshipProperty.

  `class_attribute`
    inherited from the `class_attribute` attribute of `MapperProperty`

    Return the class-bound descriptor corresponding to this `MapperProperty`.

    This is basically a `getattr()` call:

        return getattr(self.parent.class_, self.key)

    I.e. if this `MapperProperty` were named `addresses`, and the class to which it is mapped is `User`, this sequence is possible:

        >>> from sqlalchemy import inspect
        >>> mapper = inspect(User)
        >>> addresses_property = mapper.attrs.addresses
        >>> addresses_property.class_attribute is User.addresses
        True
        >>> User.addresses.property is addresses_property
        True

  `create_row_processor`(context, path, mapper, result, adapter, populators)
    inherited from the `create_row_processor()` method of `StrategizedProperty`

    Produce row processing functions and append to the given set of populators lists.

  `do_init`()

    Perform subclass-specific initialization post-mapper-creation steps.

    This is a template method called by the `MapperProperty` object’s init() method.

  `extension_type` = symbol('NOT_EXTENSION')
  `init`()
    inherited from the `init()` method of `MapperProperty`

    Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.

  `instrument_class`(mapper)

    Hook called by the Mapper to the property to initiate instrumentation of the class attribute managed by this MapperProperty.

    The MapperProperty here will typically call out to the attributes module to set up an InstrumentedAttribute.

    This step is the first of two steps to set up an InstrumentedAttribute, and is called early in the mapper setup process.

    The second step is typically the init_class_attribute step, called from StrategizedProperty via the post_instrument_class() hook. This step assigns additional state to the InstrumentedAttribute (specifically the “impl”) which has been determined after the MapperProperty has determined what kind of persistence management it needs to do (e.g. scalar, object, collection, etc).

  `mapper`

    Return the targeted `Mapper` for this `RelationshipProperty`.

    This is a lazy-initializing static attribute.

  `merge`(session, source_state, source_dict, dest_state, dest_dict, load, _recursive, _resolve_conflict_map)

    Merge the attribute represented by this `MapperProperty` from source to destination object.

  `post_instrument_class`(mapper)
    inherited from the `post_instrument_class()` method of `StrategizedProperty`

    Perform instrumentation adjustments that need to occur after init() has completed.

    The given Mapper is the Mapper invoking the operation, which may not be the same Mapper as self.parent in an inheritance scenario; however, Mapper will always at least be a sub-mapper of self.parent.

    This method is typically used by StrategizedProperty, which delegates it to LoaderStrategy.init_class_attribute() to perform final setup on the class-bound InstrumentedAttribute.

  `set_parent`(parent, init)
    inherited from the `set_parent()` method of `MapperProperty`

    Set the parent mapper that references this MapperProperty.

    This method is overridden by some subclasses to perform extra setup when the mapper is first known.

  `setup`(context, entity, path, adapter, **kwargs)
    inherited from the `setup()` method of `StrategizedProperty`

    Called by Query for the purposes of constructing a SQL statement.

    Each MapperProperty associated with the target mapper processes the statement referenced by the query context, adding columns and/or criterion as appropriate.

  `table`

    Return the selectable linked to this `RelationshipProperty` object’s target `Mapper`.

    Deprecated since version 0.7: Use .target

class `sqlalchemy.orm.descriptor_props.` `SynonymProperty`(name, map_column=None, descriptor=None, comparator_factory=None, doc=None, info=None)

  Bases: `sqlalchemy.orm.descriptor_props.DescriptorProperty`

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__init__`(name, map_column=None, descriptor=None, comparator_factory=None, doc=None, info=None)

    Construct a new `SynonymProperty` object.

    This constructor is mirrored as a public API function; see `synonym()` for a full usage and argument description.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `cascade_iterator`(type_, state, visited_instances=None, halt_on=None)
    inherited from the `cascade_iterator()` method of `MapperProperty`

    Iterate through instances related to the given instance for a particular ‘cascade’, starting with this MapperProperty.

    Return an iterator3-tuples (instance, mapper, state).

    Note that the ‘cascade’ collection on this MapperProperty is checked first for the given type before cascade_iterator is called.

    This method typically only applies to RelationshipProperty.

  `class_attribute`
    inherited from the `class_attribute` attribute of `MapperProperty`

    Return the class-bound descriptor corresponding to this `MapperProperty`.

    This is basically a `getattr()` call:

        return getattr(self.parent.class_, self.key)

    I.e. if this `MapperProperty` were named `addresses`, and the class to which it is mapped is `User`, this sequence is possible:

        >>> from sqlalchemy import inspect
        >>> mapper = inspect(User)
        >>> addresses_property = mapper.attrs.addresses
        >>> addresses_property.class_attribute is User.addresses
        True
        >>> User.addresses.property is addresses_property
        True

  `create_row_processor`(context, path, mapper, result, adapter, populators)
    inherited from the `create_row_processor()` method of `MapperProperty`

    Produce row processing functions and append to the given set of populators lists.

  `do_init`()
    inherited from the `do_init()` method of `MapperProperty`

    Perform subclass-specific initialization post-mapper-creation steps.

    This is a template method called by the `MapperProperty` object’s init() method.

  `extension_type` = symbol('NOT_EXTENSION')
  `init`()
    inherited from the `init()` method of `MapperProperty`

    Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.

  `instrument_class`(mapper)
    inherited from the `instrument_class()` method of `DescriptorProperty`

    Hook called by the Mapper to the property to initiate instrumentation of the class attribute managed by this MapperProperty.

    The MapperProperty here will typically call out to the attributes module to set up an InstrumentedAttribute.

    This step is the first of two steps to set up an InstrumentedAttribute, and is called early in the mapper setup process.

    The second step is typically the init_class_attribute step, called from StrategizedProperty via the post_instrument_class() hook. This step assigns additional state to the InstrumentedAttribute (specifically the “impl”) which has been determined after the MapperProperty has determined what kind of persistence management it needs to do (e.g. scalar, object, collection, etc).

  `merge`(session, source_state, source_dict, dest_state, dest_dict, load, _recursive, _resolve_conflict_map)
    inherited from the `merge()` method of `MapperProperty`

    Merge the attribute represented by this `MapperProperty` from source to destination object.

  `post_instrument_class`(mapper)
    inherited from the `post_instrument_class()` method of `MapperProperty`

    Perform instrumentation adjustments that need to occur after init() has completed.

    The given Mapper is the Mapper invoking the operation, which may not be the same Mapper as self.parent in an inheritance scenario; however, Mapper will always at least be a sub-mapper of self.parent.

    This method is typically used by StrategizedProperty, which delegates it to LoaderStrategy.init_class_attribute() to perform final setup on the class-bound InstrumentedAttribute.

  `set_parent`(parent, init)

    Set the parent mapper that references this MapperProperty.

    This method is overridden by some subclasses to perform extra setup when the mapper is first known.

  `setup`(context, entity, path, adapter, **kwargs)
    inherited from the `setup()` method of `MapperProperty`

    Called by Query for the purposes of constructing a SQL statement.

    Each MapperProperty associated with the target mapper processes the statement referenced by the query context, adding columns and/or criterion as appropriate.

class `sqlalchemy.orm.query.` `QueryContext`(query)

class `sqlalchemy.orm.attributes.` `QueryableAttribute`(class_, key, impl=None, comparator=None, parententity=None, of_type=None)

  Bases: `sqlalchemy.orm.base._MappedAttribute`, `sqlalchemy.orm.base.InspectionAttr`, `sqlalchemy.orm.interfaces.PropComparator`

  Base class for descriptor objects that intercept attribute events on behalf of a `MapperProperty` object. The actual `MapperProperty` is accessible via the `QueryableAttribute.property` attribute.

  See also

  `InstrumentedAttribute`

  `MapperProperty`

  `Mapper.all_orm_descriptors`

  `Mapper.attrs`

  `__eq__`(other)
    inherited from the `__eq__()` method of `ColumnOperators`

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  `__le__`(other)
    inherited from the `__le__()` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  `__lt__`(other)
    inherited from the `__lt__()` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  `__ne__`(other)
    inherited from the `__ne__()` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  `adapt_to_entity`(adapt_to_entity)

    Return a copy of this PropComparator which will use the given `AliasedInsp` to produce corresponding expressions.

  `adapter`
    inherited from the `adapter` attribute of `PropComparator`

    Produce a callable that adapts column expressions to suit an aliased version of this comparator.

  `all_`()
    inherited from the `all_()` method of `ColumnOperators`

    Produce a `all_()` clause against the parent object.

    This operator is only appropriate against a scalar subquery object, or for some backends an column expression that is against the ARRAY type, e.g.:

        # postgresql '5 = ALL (somearray)'
        expr = 5 == mytable.c.somearray.all_()

        # mysql '5 = ALL (SELECT value FROM table)'
        expr = 5 == select([table.c.value]).as_scalar().all_()

    See also

    `all_()` - standalone version

    `any_()` - ANY operator

    New in version 1.1.

  `any`(criterion=None, **kwargs)
    inherited from the `any()` method of `PropComparator`

    Return true if this collection contains any member that meets the given criterion.

    The usual implementation of `any()` is `RelationshipProperty.Comparator.any()`.

    Parameters: | criterion – an optional ClauseElement formulated against the member class’ table or attributes. **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.

  `any_`()
    inherited from the `any_()` method of `ColumnOperators`

    Produce a `any_()` clause against the parent object.

    This operator is only appropriate against a scalar subquery object, or for some backends an column expression that is against the ARRAY type, e.g.:

        # postgresql '5 = ANY (somearray)'
        expr = 5 == mytable.c.somearray.any_()

        # mysql '5 = ANY (SELECT value FROM table)'
        expr = 5 == select([table.c.value]).as_scalar().any_()

    See also

    `any_()` - standalone version

    `all_()` - ALL operator

    New in version 1.1.

  `asc`()
    inherited from the `asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  `between`(cleft, cright, symmetric=False)
    inherited from the `between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  `bool_op`(opstring, precedence=0)
    inherited from the `bool_op()` method of `Operators`

    Return a custom boolean operator.

    This method is shorthand for calling `Operators.op()` and passing the `Operators.op.is_comparison` flag with True.

    New in version 1.2.0b3.

    See also

    `Operators.op()`

  `collate`(collation)
    inherited from the `collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

    See also

    `collate()`

  `concat`(other)
    inherited from the `concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  `contains`(other, **kwargs)
    inherited from the `contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    Produces a LIKE expression that tests against a match for the middle of a string value:

        column LIKE '%' || <other> || '%'

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.contains("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.contains.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.contains.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.contains.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
          somecolumn.contains("foo%bar", autoescape=True)
      Will render as:
          somecolumn LIKE '%' || :param || '%' ESCAPE '/'
    - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.contains.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.contains.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
          somecolumn.contains("foo/%bar", escape="^")
      Will render as:
          somecolumn LIKE '%' || :param || '%' ESCAPE '^'
      The parameter may also be combined with `ColumnOperators.contains.autoescape`:
          somecolumn.contains("foo%bar^bat", escape="^", autoescape=True)
    Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

    `ColumnOperators.endswith()`

    `ColumnOperators.like()`

  `desc`()
    inherited from the `desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  `distinct`()
    inherited from the `distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  `endswith`(other, **kwargs)
    inherited from the `endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    Produces a LIKE expression that tests against a match for the end of a string value:

        column LIKE '%' || <other>

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.endswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.endswith.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.endswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.endswith.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
          somecolumn.endswith("foo%bar", autoescape=True)
      Will render as:
          somecolumn LIKE '%' || :param ESCAPE '/'
    - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.endswith.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.endswith.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
          somecolumn.endswith("foo/%bar", escape="^")
      Will render as:
          somecolumn LIKE '%' || :param ESCAPE '^'
      The parameter may also be combined with `ColumnOperators.endswith.autoescape`:
          somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)
    Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

  `extension_type` = symbol('NOT_EXTENSION')
  `has`(criterion=None, **kwargs)
    inherited from the `has()` method of `PropComparator`

    Return true if this element references a member which meets the given criterion.

    The usual implementation of `has()` is `RelationshipProperty.Comparator.has()`.

    Parameters: | criterion – an optional ClauseElement formulated against the member class’ table or attributes. **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.

  `ilike`(other, escape=None)
    inherited from the `ilike()` method of `ColumnOperators`

    Implement the `ilike` operator, e.g. case insensitive LIKE.

    In a column context, produces an expression either of the form:

        lower(a) LIKE lower(other)

    Or on backends that support the ILIKE operator:

        a ILIKE other

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.ilike("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  `in_`(other)
    inherited from the `in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

    In the case that `other` is an empty sequence, the compiler produces an “empty in” expression. This defaults to the expression “1 != 1” to produce false in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.notin_()` operators now produce a “static” expression for an empty IN sequence by default.

  `info`

    Return the ‘info’ dictionary for the underlying SQL element.

    The behavior here is as follows:

    - If the attribute is a column-mapped property, i.e. `ColumnProperty`, which is mapped directly to a schema-level `Column` object, this attribute will return the `SchemaItem.info` dictionary associated with the core-level `Column` object.
    - If the attribute is a `ColumnProperty` but is mapped to any other kind of SQL expression other than a `Column`, the attribute will refer to the `MapperProperty.info` dictionary associated directly with the `ColumnProperty`, assuming the SQL expression itself does not have its own `.info` attribute (which should be the case, unless a user-defined SQL construct has defined one).
    - If the attribute refers to any other kind of `MapperProperty`, including `RelationshipProperty`, the attribute will refer to the `MapperProperty.info` dictionary associated with that `MapperProperty`.
    - To access the `MapperProperty.info` dictionary of the `MapperProperty` unconditionally, including for a `ColumnProperty` that’s associated directly with a `schema.Column`, the attribute can be referred to using `QueryableAttribute.property` attribute, as `MyClass.someattribute.property.info`.

    New in version 0.8.0.

    See also

    `SchemaItem.info`

    `MapperProperty.info`

  `is_`(other)
    inherited from the `is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.isnot()`

  `is_distinct_from`(other)
    inherited from the `is_distinct_from()` method of `ColumnOperators`

    Implement the `IS DISTINCT FROM` operator.

    Renders “a IS DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS NOT b”.

    New in version 1.1.

  `isnot`(other)
    inherited from the `isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.is_()`

  `isnot_distinct_from`(other)
    inherited from the `isnot_distinct_from()` method of `ColumnOperators`

    Implement the `IS NOT DISTINCT FROM` operator.

    Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

    New in version 1.1.

  `like`(other, escape=None)
    inherited from the `like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the expression:

        a LIKE other

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.like("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  `match`(other, **kwargs)
    inherited from the `match()` method of `ColumnOperators`

    Implements a database-specific ‘match’ operator.

    `match()` attempts to resolve to a MATCH-like function or operator provided by the backend. Examples include:

    - PostgreSQL - renders `x @@ to_tsquery(y)`
    - MySQL - renders `MATCH (x) AGAINST (y IN BOOLEAN MODE)`
    - Oracle - renders `CONTAINS(x, y)`
    - other backends may provide special implementations.
    - Backends without any special implementation will emit the operator as “MATCH”. This is compatible with SQlite, for example.
  `notilike`(other, escape=None)
    inherited from the `notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.ilike()`

  `notin_`(other)
    inherited from the `notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.notin_()` operators now produce a “static” expression for an empty IN sequence by default.

    See also

    `ColumnOperators.in_()`

  `notlike`(other, escape=None)
    inherited from the `notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.like()`

  `nullsfirst`()
    inherited from the `nullsfirst()` method of `ColumnOperators`

    Produce a `nullsfirst()` clause against the parent object.

  `nullslast`()
    inherited from the `nullslast()` method of `ColumnOperators`

    Produce a `nullslast()` clause against the parent object.

  `of_type`(cls)

    Redefine this object in terms of a polymorphic subclass.

    Returns a new PropComparator from which further criterion can be evaluated.

    e.g.:

        query.join(Company.employees.of_type(Engineer)).\
           filter(Engineer.name=='foo')

    Parameters: | class_ – a class or mapper indicating that criterion will be against this specific subclass.

    See also

    Referring to specific subtypes on relationships

  `op`(opstring, precedence=0, is_comparison=False, return_type=None)
    inherited from the `op()` method of `Operators`

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument. is_comparison – if True, the operator will be considered as a “comparison” operator, that is which evaluates to a boolean true/false value, like `==`, `>`, etc. This flag should be set so that ORM relationships can establish that the operator is a comparison operator when used in a custom join condition. New in version 0.9.2: - added the `Operators.op.is_comparison` flag. return_type – a `TypeEngine` class or object that will force the return type of an expression produced by this operator to be of that type. By default, operators that specify `Operators.op.is_comparison` will resolve to `Boolean`, and those that do not will be of the same type as the left-hand operand. New in version 1.2.0b3: - added the `Operators.op.return_type` argument.

    See also

    Redefining and Creating New Operators

    Using custom operators in join conditions

  `operate`(op, *other, **kwargs)

    Operate on an argument.

    This is the lowest level of operation, raises `NotImplementedError` by default.

    Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding `ColumnOperators` to apply `func.lower()` to the left and right side:

        class MyComparator(ColumnOperators):
            def operate(self, op, other):
                return op(func.lower(self), func.lower(other))

    Parameters: | op – Operator callable. *other – the ‘other’ side of the operation. Will be a single scalar for most operations. **kwargs – modifiers. These may be passed by special operators such as `ColumnOperators.contains()`.

  `parent`

    Return an inspection instance representing the parent.

    This will be either an instance of `Mapper` or `AliasedInsp`, depending upon the nature of the parent entity which this attribute is associated with.

  `property`

    Return the `MapperProperty` associated with this `QueryableAttribute`.

    Return values here will commonly be instances of `ColumnProperty` or `RelationshipProperty`.

  `reverse_operate`(op, other, **kwargs)

    Reverse operate on an argument.

    Usage is the same as `operate()`.

  `startswith`(other, **kwargs)
    inherited from the `startswith()` method of `ColumnOperators`

    Implement the `startswith` operator.

    Produces a LIKE expression that tests against a match for the start of a string value:

        column LIKE <other> || '%'

    E.g.:

        stmt = select([sometable]).\
            where(sometable.c.column.startswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.startswith.autoescape` flag may be set to `True` to apply escaping to occurences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.startswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    - Parameters: | other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.startswith.autoescape` flag is set to True. autoescape – boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression. An expression such as:
          somecolumn.startswith("foo%bar", autoescape=True)
      Will render as:
          somecolumn LIKE :param || '%' ESCAPE '/'
    - With the value of :param as `"foo/%bar"`. New in version 1.2. Changed in version 1.2.0: The `ColumnOperators.startswith.autoescape` parameter is now a simple boolean rather than a character; the escape character itself is also escaped, and defaults to a forwards slash, which itself can be customized using the `ColumnOperators.startswith.escape` parameter. escape – a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters. An expression such as:
          somecolumn.startswith("foo/%bar", escape="^")
      Will render as:
          somecolumn LIKE :param || '%' ESCAPE '^'
      The parameter may also be combined with `ColumnOperators.startswith.autoescape`:
          somecolumn.startswith("foo%bar^bat", escape="^", autoescape=True)
    Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.endswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

class `sqlalchemy.orm.session.` `UOWTransaction`(session)
  `filter_states_for_dep`(dep, states)

    Filter the given list of InstanceStates to those relevant to the given DependencyProcessor.

  `finalize_flush_changes`()

    mark processed objects as clean / deleted after a successful flush().

    this method is called within the flush() method after the execute() method has succeeded and the transaction has been committed.

  `get_attribute_history`(state, key, passive=symbol('PASSIVE_NO_INITIALIZE'))

    facade to attributes.get_state_history(), including caching of results.

  `is_deleted`(state)

    return true if the given state is marked as deleted within this uowtransaction.

  `remove_state_actions`(state)

    remove pending actions for a state from the uowtransaction.

  `was_already_deleted`(state)

    return true if the given state is expired and was deleted previously.