9.5.4. /db/_design/design-doc/_view/view-name — Apache CouchDB 1.7 Documentation

# 9.5.4. `/db/_design/design-doc/_view/view-name`

`GET` `/{db}/_design/{ddoc}/_view/{view}`

  Executes the specified view function from the specified design document.

  Parameters: | db – Database name ddoc – Design document name view – View function name
  Request Headers:
  | Accept – application/json text/plain
  Query Parameters:
  | conflicts (boolean) – Includes conflicts information in response. Ignored if include_docs isn’t `true`. Default is `false` descending (boolean) – Return the documents in descending by key order. Default is `false` endkey (json) – Stop returning records when the specified key is reached. Optional end_key (json) – Alias for endkey param endkey_docid (string) – Stop returning records when the specified document ID is reached. Optional end_key_doc_id (string) – Alias for endkey_docid param group (boolean) – Group the results using the reduce function to a group or single row. Default is `false` group_level (number) – Specify the group level to be used. Optional include_docs (boolean) – Include the associated document with each row. Default is `false`. attachments (boolean) – Include the Base64-encoded content of attachments in the documents that are included if include_docs is `true`. Ignored if include_docs isn’t `true`. Default is `false`. att_encoding_info (boolean) – Include encoding information in attachment stubs if include_docs is `true` and the particular attachment is compressed. Ignored if include_docs isn’t `true`. Default is `false`. inclusive_end (boolean) – Specifies whether the specified end key should be included in the result. Default is `true` key (json) – Return only documents that match the specified key. Optional keys (json-array) – Return only documents where the key matches one of the keys specified in the array. Optional limit (number) – Limit the number of the returned documents to the specified number. Optional reduce (boolean) – Use the reduction function. Default is `true` skip (number) – Skip this number of records before starting to return the results. Default is `0` stale (string) – Allow the results from a stale view to be used. Supported values: `ok` and `update_after`. Optional startkey (json) – Return records starting with the specified key. Optional start_key (json) – Alias for startkey param startkey_docid (string) – Return records starting with the specified document ID. Optional start_key_doc_id (string) – Alias for startkey_docid param update_seq (boolean) – Response includes an `update_seq` value indicating which sequence id of the database the view reflects. Default is `false`
  Response Headers:
  | Content-Type – application/json text/plain; charset=utf-8 ETag – Response signature Transfer-Encoding – `chunked`
  Response JSON Object:
  | offset (number) – Offset where the document list started rows (array) – Array of view row objects. By default the information returned contains only the document ID and revision total_rows (number) – Number of documents in the database/view update_seq (number) – Current update sequence for the database
  Status Codes: | 200 OK – Request completed successfully 400 Bad Request – Invalid request 401 Unauthorized – Read permission required 404 Not Found – Specified database, design document or view is missed 500 Internal Server Error – View function execution error

  Request:

      GET /recipes/_design/ingredients/_view/by_name HTTP/1.1
      Accept: application/json
      Host: localhost:5984

  Response:

      HTTP/1.1 200 OK
      Cache-Control: must-revalidate
      Content-Type: application/json
      Date: Wed, 21 Aug 2013 09:12:06 GMT
      ETag: "2FOLSBSW4O6WB798XU4AQYA9B"
      Server: CouchDB (Erlang/OTP)
      Transfer-Encoding: chunked

      {
          "offset": 0,
          "rows": [
              {
                  "id": "SpaghettiWithMeatballs",
                  "key": "meatballs",
                  "value": 1
              },
              {
                  "id": "SpaghettiWithMeatballs",
                  "key": "spaghetti",
                  "value": 1
              },
              {
                  "id": "SpaghettiWithMeatballs",
                  "key": "tomato sauce",
                  "value": 1
              }
          ],
          "total_rows": 3
      }

Changed in version 1.6.0: added `attachments` and `att_encoding_info` parameters

Warning

Using the `attachments` parameter to include attachments in view results is not recommended for large attachment sizes. Also note that the Base64-encoding that is used leads to a 33% overhead (i.e. one third) in transfer size for attachments.

`POST` `/{db}/_design/{ddoc}/_view/{view}`

  Executes the specified view function from the specified design document. Unlike `GET /{db}/_design/{ddoc}/_view/{view}` for accessing views, the POST method supports the specification of explicit keys to be retrieved from the view results. The remainder of the POST view functionality is identical to the `GET /{db}/_design/{ddoc}/_view/{view}` API.

  Request:

      POST /recipes/_design/ingredients/_view/by_name HTTP/1.1
      Accept: application/json
      Content-Length: 37
      Host: localhost:5984

      {
          "keys": [
              "meatballs",
              "spaghetti"
          ]
      }

  Response:

      HTTP/1.1 200 OK
      Cache-Control: must-revalidate
      Content-Type: application/json
      Date: Wed, 21 Aug 2013 09:14:13 GMT
      ETag: "6R5NM8E872JIJF796VF7WI3FZ"
      Server: CouchDB (Erlang/OTP)
      Transfer-Encoding: chunked

      {
          "offset": 0,
          "rows": [
              {
                  "id": "SpaghettiWithMeatballs",
                  "key": "meatballs",
                  "value": 1
              },
              {
                  "id": "SpaghettiWithMeatballs",
                  "key": "spaghetti",
                  "value": 1
              }
          ],
          "total_rows": 3
      }

## View Options

There are two view indexing options that can be defined in a design document as boolean properties of an `options` object. Unlike the others querying options, these aren’t URL parameters because they take effect when the view index is generated, not when it’s accessed:

- local_seq (boolean): Makes documents’ local sequence numbers available to map functions (as a `_local_seq` document property)
- include_design (boolean): Allows map functions to be called on design documents as well as regular documents

In additional to these options, you may specify any other with their default value. E.g. having option `"include_docs": true` will automatically includes document body for view results response. You still may override such by explicitly defining same query parameter name with other value.

## Querying Views and Indexes

The definition of a view within a design document also creates an index based on the key information defined within each view. The production and use of the index significantly increases the speed of access and searching or selecting documents from the view.

However, the index is not updated when new documents are added or modified in the database. Instead, the index is generated or updated, either when the view is first accessed, or when the view is accessed after a document has been updated. In each case, the index is updated before the view query is executed against the database.

View indexes are updated incrementally in the following situations:

- A new document has been added to the database.
- A document has been deleted from the database.
- A document in the database has been updated.

View indexes are rebuilt entirely when the view definition changes. To achieve this, a ‘fingerprint’ of the view definition is created when the design document is updated. If the fingerprint changes, then the view indexes are entirely rebuilt. This ensures that changes to the view definitions are reflected in the view indexes.

Note

View index rebuilds occur when one view from the same the view group (i.e. all the views defined within a single a design document) has been determined as needing a rebuild. For example, if if you have a design document with different views, and you update the database, all three view indexes within the design document will be updated.

Because the view is updated when it has been queried, it can result in a delay in returned information when the view is accessed, especially if there are a large number of documents in the database and the view index does not exist. There are a number of ways to mitigate, but not completely eliminate, these issues. These include:

- Create the view definition (and associated design documents) on your database before allowing insertion or updates to the documents. If this is allowed while the view is being accessed, the index can be updated incrementally.
- Manually force a view request from the database. You can do this either before users are allowed to use the view, or you can access the view manually after documents are added or updated.
- Use the changes feed to monitor for changes to the database and then access the view to force the corresponding view index to be updated.
- Use a monitor with the update notification section of the CouchDB configuration file to monitor for changes to your database, and trigger a view query to force the view to be updated.

None of these can completely eliminate the need for the indexes to be rebuilt or updated when the view is accessed, but they may lessen the effects on end-users of the index update affecting the user experience.

Another alternative is to allow users to access a ‘stale’ version of the view index, rather than forcing the index to be updated and displaying the updated results. Using a stale view may not return the latest information, but will return the results of the view query using an existing version of the index.

For example, to access the existing stale view `by_recipe` in the `recipes` design document:

    http://localhost:5984/recipes/_design/recipes/_view/by_recipe?stale=ok

Accessing a stale view:

- Does not trigger a rebuild of the view indexes, even if there have been changes since the last access.
- Returns the current version of the view index, if a current version exists.
- Returns an empty result set if the given view index does exist.

As an alternative, you use the `update_after` value to the `stale` parameter. This causes the view to be returned as a stale view, but for the update process to be triggered after the view information has been returned to the client.

In addition to using stale views, you can also make use of the `update_seq` query argument. Using this query argument generates the view information including the update sequence of the database from which the view was generated. The returned value can be compared this to the current update sequence exposed in the database information (returned by `GET /{db}`).

## Sorting Returned Rows

Each element within the returned array is sorted using native UTF-8 sorting according to the contents of the key portion of the emitted content. The basic order of output is as follows:

- `null`
- `false`
- `true`
- Numbers
- Text (case sensitive, lowercase first)
- Arrays (according to the values of each element, in order)
- Objects (according to the values of keys, in key order)

Request:

    GET /db/_design/test/_view/sorting HTTP/1.1
    Accept: application/json
    Host: localhost:5984

Response:

    HTTP/1.1 200 OK
    Cache-Control: must-revalidate
    Content-Type: application/json
    Date: Wed, 21 Aug 2013 10:09:25 GMT
    ETag: "8LA1LZPQ37B6R9U8BK9BGQH27"
    Server: CouchDB (Erlang/OTP)
    Transfer-Encoding: chunked

    {
        "offset": 0,
        "rows": [
            {
                "id": "dummy-doc",
                "key": null,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": false,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": true,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": 0,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": 1,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": 10,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": 42,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": "10",
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": "hello",
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": "Hello",
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": "\u043f\u0440\u0438\u0432\u0435\u0442",
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": [],
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": [
                    1,
                    2,
                    3
                ],
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": [
                    2,
                    3
                ],
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": [
                    3
                ],
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": {},
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": {
                    "foo": "bar"
                },
                "value": null
            }
        ],
        "total_rows": 17
    }

You can reverse the order of the returned view information by using the `descending` query value set to true:

Request:

    GET /db/_design/test/_view/sorting?descending=true HTTP/1.1
    Accept: application/json
    Host: localhost:5984

Response:

    HTTP/1.1 200 OK
    Cache-Control: must-revalidate
    Content-Type: application/json
    Date: Wed, 21 Aug 2013 10:09:25 GMT
    ETag: "Z4N468R15JBT98OM0AMNSR8U"
    Server: CouchDB (Erlang/OTP)
    Transfer-Encoding: chunked

    {
        "offset": 0,
        "rows": [
            {
                "id": "dummy-doc",
                "key": {
                    "foo": "bar"
                },
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": {},
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": [
                    3
                ],
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": [
                    2,
                    3
                ],
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": [
                    1,
                    2,
                    3
                ],
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": [],
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": "\u043f\u0440\u0438\u0432\u0435\u0442",
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": "Hello",
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": "hello",
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": "10",
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": 42,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": 10,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": 1,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": 0,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": true,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": false,
                "value": null
            },
            {
                "id": "dummy-doc",
                "key": null,
                "value": null
            }
        ],
        "total_rows": 17
    }

### Sorting order and startkey/endkey

The sorting direction is applied before the filtering applied using the `startkey` and `endkey` query arguments. For example the following query:

    GET http://couchdb:5984/recipes/_design/recipes/_view/by_ingredient?startkey=%22carrots%22&endkey=%22egg%22
    Accept: application/json

will operate correctly when listing all the matching entries between `carrots` and `egg`. If the order of output is reversed with the `descending` query argument, the view request will return no entries:

    GET /recipes/_design/recipes/_view/by_ingredient?descending=true&startkey=%22carrots%22&endkey=%22egg%22 HTTP/1.1
    Accept: application/json
    Host: localhost:5984

    {
       "total_rows" : 26453,
       "rows" : [],
       "offset" : 21882
    }

The results will be empty because the entries in the view are reversed before the key filter is applied, and therefore the `endkey` of “egg” will be seen before the `startkey` of “carrots”, resulting in an empty list.

Instead, you should reverse the values supplied to the `startkey` and `endkey` parameters to match the descending sorting applied to the keys. Changing the previous example to:

    GET /recipes/_design/recipes/_view/by_ingredient?descending=true&startkey=%22egg%22&endkey=%22carrots%22 HTTP/1.1
    Accept: application/json
    Host: localhost:5984

### Raw collation

By default CouchDB using ICU driver for sorting view results. It’s possible use binary collation instead for faster view builds where Unicode collation is not important.

To use raw collation add `"collation": "raw"` key-value pair to the design documents `options` object at the root level. After that, views will be regenerated and new order applied.

See also

Views Collation

## Using Limits and Skipping Rows

By default requestion views result returns all records for it. That’s ok when they are small, but this may lead to problems when there are billions of them since the clients might have to read them all and consume all available memory.

But it’s possible to reduce output result rows by specifying `limit` query parameter. For example, retrieving the list of recipes using the `by_title` view and limited to 5 returns only 5 records, while there are total 2667 records in view:

Request:

    GET /recipes/_design/recipes/_view/by_title?limit=5 HTTP/1.1
    Accept: application/json
    Host: localhost:5984

Response:

    HTTP/1.1 200 OK
    Cache-Control: must-revalidate
    Content-Type: application/json
    Date: Wed, 21 Aug 2013 09:14:13 GMT
    ETag: "9Q6Q2GZKPH8D5F8L7PB6DBSS9"
    Server: CouchDB (Erlang/OTP)
    Transfer-Encoding: chunked

    {
       "offset" : 0,
       "rows" : [
          {
             "id" : "3-tiersalmonspinachandavocadoterrine",
             "key" : "3-tier salmon, spinach and avocado terrine",
             "value" : [
                null,
                "3-tier salmon, spinach and avocado terrine"
             ]
          },
          {
             "id" : "Aberffrawcake",
             "key" : "Aberffraw cake",
             "value" : [
                null,
                "Aberffraw cake"
             ]
          },
          {
             "id" : "Adukiandorangecasserole-microwave",
             "key" : "Aduki and orange casserole - microwave",
             "value" : [
                null,
                "Aduki and orange casserole - microwave"
             ]
          },
          {
             "id" : "Aioli-garlicmayonnaise",
             "key" : "Aioli - garlic mayonnaise",
             "value" : [
                null,
                "Aioli - garlic mayonnaise"
             ]
          },
          {
             "id" : "Alabamapeanutchicken",
             "key" : "Alabama peanut chicken",
             "value" : [
                null,
                "Alabama peanut chicken"
             ]
          }
       ],
       "total_rows" : 2667
    }

To omit some records you may use `skip` query parameter:

Request:

    GET /recipes/_design/recipes/_view/by_title?limit=3&skip=2 HTTP/1.1
    Accept: application/json
    Host: localhost:5984

Response:

    HTTP/1.1 200 OK
    Cache-Control: must-revalidate
    Content-Type: application/json
    Date: Wed, 21 Aug 2013 09:14:13 GMT
    ETag: "H3G7YZSNIVRRHO5FXPE16NJHN"
    Server: CouchDB (Erlang/OTP)
    Transfer-Encoding: chunked

    {
       "offset" : 2,
       "rows" : [
          {
             "id" : "Adukiandorangecasserole-microwave",
             "key" : "Aduki and orange casserole - microwave",
             "value" : [
                null,
                "Aduki and orange casserole - microwave"
             ]
          },
          {
             "id" : "Aioli-garlicmayonnaise",
             "key" : "Aioli - garlic mayonnaise",
             "value" : [
                null,
                "Aioli - garlic mayonnaise"
             ]
          },
          {
             "id" : "Alabamapeanutchicken",
             "key" : "Alabama peanut chicken",
             "value" : [
                null,
                "Alabama peanut chicken"
             ]
          }
       ],
       "total_rows" : 2667
    }

Warning

Using `limit` and `skip` parameters is not recommended for results pagination. Read pagination recipe why it’s so and how to make it better.