# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
#
# This Source Code Form is "Incompatible With Secondary Licenses", as
# defined by the Mozilla Public License, v. 2.0.

=head1 NAME

Bugzilla::DB::Oracle - Bugzilla database compatibility layer for Oracle

=head1 DESCRIPTION

This module overrides methods of the Bugzilla::DB module with Oracle
specific implementation. It is instantiated by the Bugzilla::DB module
and should never be used directly.

For interface details see L<Bugzilla::DB> and L<DBI>.

=cut

package Bugzilla::DB::Oracle;

use 5.10.1;
use strict;
use warnings;

use parent qw(Bugzilla::DB);

use DBD::Oracle;
use DBD::Oracle qw(:ora_types);
use List::Util qw(max);

use Bugzilla::Constants;
use Bugzilla::Error;
use Bugzilla::Util;

#####################################################################
# Constants
#####################################################################
use constant EMPTY_STRING    => '__BZ_EMPTY_STR__';
use constant ISOLATION_LEVEL => 'READ COMMITTED';
use constant BLOB_TYPE       => {ora_type => ORA_BLOB};

# The max size allowed for LOB fields, in kilobytes.
use constant MIN_LONG_READ_LEN => 32 * 1024;
use constant FULLTEXT_OR       => ' OR ';

sub new {
  my ($class, $params) = @_;
  my ($user, $pass, $host, $dbname, $port)
    = @$params{qw(db_user db_pass db_host db_name db_port)};

  # You can never connect to Oracle without a DB name,
  # and there is no default DB.
  $dbname ||= Bugzilla->localconfig->{db_name};

  # Set the language enviroment
  $ENV{'NLS_LANG'} = '.AL32UTF8' if Bugzilla->params->{'utf8'};

  # construct the DSN from the parameters we got
  my $dsn = "dbi:Oracle:host=$host;sid=$dbname";
  $dsn .= ";port=$port" if $port;
  my $attrs = {
    FetchHashKeyName => 'NAME_lc',
    LongReadLen =>
      max(Bugzilla->params->{'maxattachmentsize'} || 0, MIN_LONG_READ_LEN) * 1024,
  };
  my $self = $class->db_new(
    {dsn => $dsn, user => $user, pass => $pass, attrs => $attrs});

  # Needed by TheSchwartz
  $self->{private_bz_dsn} = $dsn;

  bless($self, $class);

  # Set the session's default date format to match MySQL
  $self->do("ALTER SESSION SET NLS_DATE_FORMAT='YYYY-MM-DD HH24:MI:SS'");
  $self->do("ALTER SESSION SET NLS_TIMESTAMP_FORMAT='YYYY-MM-DD HH24:MI:SS'");
  $self->do("ALTER SESSION SET NLS_LENGTH_SEMANTICS='CHAR'")
    if Bugzilla->params->{'utf8'};

  # To allow case insensitive query.
  $self->do("ALTER SESSION SET NLS_COMP='ANSI'");
  $self->do("ALTER SESSION SET NLS_SORT='BINARY_AI'");
  return $self;
}

sub bz_last_key {
  my ($self, $table, $column) = @_;

  my $seq = $table . "_" . $column . "_SEQ";
  my ($last_insert_id)
    = $self->selectrow_array("SELECT $seq.CURRVAL " . " FROM DUAL");
  return $last_insert_id;
}

sub bz_check_regexp {
  my ($self, $pattern) = @_;

  eval {
    $self->do("SELECT 1 FROM DUAL WHERE "
        . $self->sql_regexp($self->quote("a"), $pattern, 1));
  };

  $@
    && ThrowUserError('illegal_regexp',
    {value => $pattern, dberror => $self->errstr});
}

sub bz_explain {
  my ($self, $sql) = @_;
  my $sth = $self->prepare("EXPLAIN PLAN FOR $sql");
  $sth->execute();
  my $explain = $self->selectcol_arrayref(
    "SELECT PLAN_TABLE_OUTPUT FROM TABLE(DBMS_XPLAN.DISPLAY)");
  return join("\n", @$explain);
}

sub sql_group_concat {
  my ($self, $text, $separator) = @_;
  $separator = $self->quote(', ') if !defined $separator;
  my ($distinct, $rest) = $text =~ /^(\s*DISTINCT\s|)(.+)$/i;
  return "group_concat($distinct T_CLOB_DELIM(NVL($rest, ' '), $separator))";
}

sub sql_regexp {
  my ($self, $expr, $pattern, $nocheck, $real_pattern) = @_;
  $real_pattern ||= $pattern;

  $self->bz_check_regexp($real_pattern) if !$nocheck;

  return "REGEXP_LIKE($expr, $pattern)";
}

sub sql_not_regexp {
  my ($self, $expr, $pattern, $nocheck, $real_pattern) = @_;
  $real_pattern ||= $pattern;

  $self->bz_check_regexp($real_pattern) if !$nocheck;

  return "NOT REGEXP_LIKE($expr, $pattern)";
}

sub sql_limit {
  my ($self, $limit, $offset) = @_;

  if (defined $offset) {
    return "/* LIMIT $limit $offset */";
  }
  return "/* LIMIT $limit */";
}

sub sql_string_concat {
  my ($self, @params) = @_;

  return 'CONCAT(' . join(', ', @params) . ')';
}

sub sql_to_days {
  my ($self, $date) = @_;

  return " TO_CHAR(TO_DATE($date),'J') ";
}

sub sql_from_days {
  my ($self, $date) = @_;

  return " TO_DATE($date,'J') ";
}

sub sql_fulltext_search {
  my ($self, $column, $text) = @_;
  state $label = 0;
  $text = $self->quote($text);
  trick_taint($text);
  $label++;
  return "CONTAINS($column,$text,$label) > 0", "SCORE($label)";
}

sub sql_date_format {
  my ($self, $date, $format) = @_;

  $format = "%Y.%m.%d %H:%i:%s" if !$format;

  $format =~ s/\%Y/YYYY/g;
  $format =~ s/\%y/YY/g;
  $format =~ s/\%m/MM/g;
  $format =~ s/\%d/DD/g;
  $format =~ s/\%a/Dy/g;
  $format =~ s/\%H/HH24/g;
  $format =~ s/\%i/MI/g;
  $format =~ s/\%s/SS/g;

  return "TO_CHAR($date, " . $self->quote($format) . ")";
}

sub sql_date_math {
  my ($self, $date, $operator, $interval, $units) = @_;
  my $time_sql;
  if ($units =~ /YEAR|MONTH/i) {
    $time_sql = "NUMTOYMINTERVAL($interval,'$units')";
  }
  else {
    $time_sql = "NUMTODSINTERVAL($interval,'$units')";
  }
  return "$date $operator $time_sql";
}

sub sql_position {
  my ($self, $fragment, $text) = @_;
  return "INSTR($text, $fragment)";
}

sub sql_in {
  my ($self, $column_name, $in_list_ref, $negate) = @_;
  my @in_list = @$in_list_ref;
  return $self->SUPER::sql_in($column_name, $in_list_ref, $negate)
    if $#in_list < 1000;
  my @in_str;
  while (@in_list) {
    my $length      = $#in_list + 1;
    my $splice      = $length > 1000 ? 1000 : $length;
    my @sub_in_list = splice(@in_list, 0, $splice);
    push(@in_str, $self->SUPER::sql_in($column_name, \@sub_in_list, $negate));
  }
  return "( " . join(" OR ", @in_str) . " )";
}

sub _bz_add_field_table {
  my ($self, $name, $schema_ref, $type) = @_;
  $self->SUPER::_bz_add_field_table($name, $schema_ref);
  if (defined($type) && $type == FIELD_TYPE_MULTI_SELECT) {
    my $uk_name = "UK_" . $self->_bz_schema->_hash_identifier($name . '_value');
    $self->do("ALTER TABLE $name ADD CONSTRAINT $uk_name UNIQUE(value)");
  }
}

sub bz_drop_table {
  my ($self, $name) = @_;
  my $table_exists = $self->bz_table_info($name);
  if ($table_exists) {
    $self->_bz_drop_fks($name);
    $self->SUPER::bz_drop_table($name);
  }
}

# Dropping all FKs for a specified table.
sub _bz_drop_fks {
  my ($self, $table) = @_;
  my @columns = $self->bz_table_columns($table);
  foreach my $column (@columns) {
    $self->bz_drop_fk($table, $column);
  }
}

sub _fix_empty {
  my ($string) = @_;
  $string = '' if $string eq EMPTY_STRING;
  return $string;
}

sub _fix_arrayref {
  my ($row) = @_;
  return undef if !defined $row;
  foreach my $field (@$row) {
    $field = _fix_empty($field) if defined $field;
  }
  return $row;
}

sub _fix_hashref {
  my ($row) = @_;
  return undef if !defined $row;
  foreach my $value (values %$row) {
    $value = _fix_empty($value) if defined $value;
  }
  return $row;
}

sub adjust_statement {
  my ($sql) = @_;

  if ($sql =~ /^CREATE OR REPLACE.*/i) {
    return $sql;
  }

  # We can't just assume any occurrence of "''" in $sql is an empty
  # string, since "''" can occur inside a string literal as a way of
  # escaping a single "'" in the literal.  Therefore we must be trickier...

  # split the statement into parts by single-quotes.  The negative value
  # at the end to the split operator from dropping trailing empty strings
  # (e.g., when $sql ends in "''")
  my @parts = split /'/, $sql, -1;

  if (!(@parts % 2)) {

    # Either the string is empty or the quotes are mismatched
    # Returning input unmodified.
    return $sql;
  }

  # We already verified that we have an odd number of parts.  If we take
  # the first part off now, we know we're entering the loop with an even
  # number of parts
  my @result;
  my $part = shift @parts;

  # Oracle requires a FROM clause in all SELECT statements, so append
  # "FROM dual" to queries without one (e.g., "SELECT NOW()")
  my $is_select = ($part =~ m/^\s*SELECT\b/io);
  my $has_from  = ($part =~ m/\bFROM\b/io) if $is_select;

  # Oracle includes the time in CURRENT_DATE.
  $part =~ s/\bCURRENT_DATE\b/TRUNC(CURRENT_DATE)/io;

  # Oracle use SUBSTR instead of SUBSTRING
  $part =~ s/\bSUBSTRING\b/SUBSTR/io;

  # Oracle need no 'AS'
  $part =~ s/\bAS\b//ig;

  # Oracle doesn't have LIMIT, so if we find the LIMIT comment, wrap the
  # query with "SELECT * FROM (...) WHERE rownum < $limit"
  my ($limit, $offset) = ($part =~ m{/\* LIMIT (\d*) (\d*) \*/}o);

  push @result, $part;
  while (@parts) {
    my $string    = shift @parts;
    my $nonstring = shift @parts;

    # if the non-string part is zero-length and there are more parts left,
    # then this is an escaped quote inside a string literal
    while (!(length $nonstring) && @parts) {

      # we know it's safe to remove two parts at a time, since we
      # entered the loop with an even number of parts
      $string .= "''" . shift @parts;
      $nonstring = shift @parts;
    }

    # Look for a FROM if this is a SELECT and we haven't found one yet
    $has_from = ($nonstring =~ m/\bFROM\b/io) if ($is_select and !$has_from);

    # Oracle includes the time in CURRENT_DATE.
    $nonstring =~ s/\bCURRENT_DATE\b/TRUNC(CURRENT_DATE)/io;

    # Oracle use SUBSTR instead of SUBSTRING
    $nonstring =~ s/\bSUBSTRING\b/SUBSTR/io;

    # Oracle need no 'AS'
    $nonstring =~ s/\bAS\b//ig;

    # Look for a LIMIT clause
    ($limit) = ($nonstring =~ m(/\* LIMIT (\d*) \*/)o);

    if (!length($string)) {
      push @result, EMPTY_STRING;
      push @result, $nonstring;
    }
    else {
      push @result, $string;
      push @result, $nonstring;
    }
  }

  my $new_sql = join "'", @result;

  # Append "FROM dual" if this is a SELECT without a FROM clause
  $new_sql .= " FROM DUAL" if ($is_select and !$has_from);

  # Wrap the query with a "WHERE rownum <= ..." if we found LIMIT

  if (defined($limit)) {
    if ($new_sql !~ /\bWHERE\b/) {
      $new_sql = $new_sql . " WHERE 1=1";
    }
    my ($before_where, $after_where) = split(/\bWHERE\b/i, $new_sql, 2);
    if (defined($offset)) {
      my ($before_from, $after_from) = split(/\bFROM\b/i, $new_sql, 2);
      $before_where
        = "$before_from FROM ($before_from,"
        . " ROW_NUMBER() OVER (ORDER BY 1) R "
        . " FROM $after_from ) ";
      $after_where = " R BETWEEN $offset+1 AND $limit+$offset";
    }
    else {
      $after_where = " rownum <=$limit AND " . $after_where;
    }
    $new_sql = $before_where . " WHERE " . $after_where;
  }
  return $new_sql;
}

sub do {
  my $self = shift;
  my $sql  = shift;
  $sql = adjust_statement($sql);
  unshift @_, $sql;
  return $self->SUPER::do(@_);
}

sub selectrow_array {
  my $self     = shift;
  my $stmt     = shift;
  my $new_stmt = (ref $stmt) ? $stmt : adjust_statement($stmt);
  unshift @_, $new_stmt;
  if (wantarray) {
    my @row = $self->SUPER::selectrow_array(@_);
    _fix_arrayref(\@row);
    return @row;
  }
  else {
    my $row = $self->SUPER::selectrow_array(@_);
    $row = _fix_empty($row) if defined $row;
    return $row;
  }
}

sub selectrow_arrayref {
  my $self     = shift;
  my $stmt     = shift;
  my $new_stmt = (ref $stmt) ? $stmt : adjust_statement($stmt);
  unshift @_, $new_stmt;
  my $ref = $self->SUPER::selectrow_arrayref(@_);
  return undef if !defined $ref;

  _fix_arrayref($ref);
  return $ref;
}

sub selectrow_hashref {
  my $self     = shift;
  my $stmt     = shift;
  my $new_stmt = (ref $stmt) ? $stmt : adjust_statement($stmt);
  unshift @_, $new_stmt;
  my $ref = $self->SUPER::selectrow_hashref(@_);
  return undef if !defined $ref;

  _fix_hashref($ref);
  return $ref;
}

sub selectall_arrayref {
  my $self     = shift;
  my $stmt     = shift;
  my $new_stmt = (ref $stmt) ? $stmt : adjust_statement($stmt);
  unshift @_, $new_stmt;
  my $ref = $self->SUPER::selectall_arrayref(@_);
  return undef if !defined $ref;

  foreach my $row (@$ref) {
    if (ref($row) eq 'ARRAY') {
      _fix_arrayref($row);
    }
    elsif (ref($row) eq 'HASH') {
      _fix_hashref($row);
    }
  }

  return $ref;
}

sub selectall_hashref {
  my $self     = shift;
  my $stmt     = shift;
  my $new_stmt = (ref $stmt) ? $stmt : adjust_statement($stmt);
  unshift @_, $new_stmt;
  my $rows = $self->SUPER::selectall_hashref(@_);
  return undef if !defined $rows;
  foreach my $row (values %$rows) {
    _fix_hashref($row);
  }
  return $rows;
}

sub selectcol_arrayref {
  my $self     = shift;
  my $stmt     = shift;
  my $new_stmt = (ref $stmt) ? $stmt : adjust_statement($stmt);
  unshift @_, $new_stmt;
  my $ref = $self->SUPER::selectcol_arrayref(@_);
  return undef if !defined $ref;
  _fix_arrayref($ref);
  return $ref;
}

sub prepare {
  my $self    = shift;
  my $sql     = shift;
  my $new_sql = adjust_statement($sql);
  unshift @_, $new_sql;
  return bless $self->SUPER::prepare(@_), 'Bugzilla::DB::Oracle::st';
}

sub prepare_cached {
  my $self    = shift;
  my $sql     = shift;
  my $new_sql = adjust_statement($sql);
  unshift @_, $new_sql;
  return bless $self->SUPER::prepare_cached(@_), 'Bugzilla::DB::Oracle::st';
}

sub quote_identifier {
  my ($self, $id) = @_;
  return $id;
}

#####################################################################
# Protected "Real Database" Schema Information Methods
#####################################################################

sub bz_table_columns_real {
  my ($self, $table) = @_;
  $table = uc($table);
  my $cols = $self->selectcol_arrayref(
    "SELECT LOWER(COLUMN_NAME) FROM USER_TAB_COLUMNS WHERE 
         TABLE_NAME = ?  ORDER BY COLUMN_NAME", undef, $table
  );
  return @$cols;
}

sub bz_table_list_real {
  my ($self) = @_;
  my $tables = $self->selectcol_arrayref(
    "SELECT LOWER(TABLE_NAME) FROM USER_TABLES WHERE 
        TABLE_NAME NOT LIKE ?  ORDER BY TABLE_NAME", undef, 'DR$%'
  );
  return @$tables;
}

#####################################################################
# Custom Database Setup
#####################################################################

sub bz_setup_database {
  my $self = shift;

  # Create a function that returns SYSDATE to emulate MySQL's "NOW()".
  # Function NOW() is used widely in Bugzilla SQLs, but Oracle does not
  # have that function, So we have to create one ourself.
  $self->do("CREATE OR REPLACE FUNCTION NOW "
      . " RETURN DATE IS BEGIN RETURN SYSDATE; END;");
  $self->do("CREATE OR REPLACE FUNCTION CHAR_LENGTH(COLUMN_NAME VARCHAR2)"
      . " RETURN NUMBER IS BEGIN RETURN LENGTH(COLUMN_NAME); END;");

  # Create types for group_concat
  my $type_exists = $self->selectrow_array(
    "SELECT 1 FROM user_types
                                              WHERE type_name = 'T_GROUP_CONCAT'"
  );
  $self->do("DROP TYPE T_GROUP_CONCAT") if $type_exists;
  $self->do("CREATE OR REPLACE TYPE T_CLOB_DELIM AS OBJECT "
      . "( p_CONTENT CLOB, p_DELIMITER VARCHAR2(256)"
      . ", MAP MEMBER FUNCTION T_CLOB_DELIM_ToVarchar return VARCHAR2"
      . ");");
  $self->do(
    "CREATE OR REPLACE TYPE BODY T_CLOB_DELIM IS
                  MAP MEMBER FUNCTION T_CLOB_DELIM_ToVarchar return VARCHAR2 is
                  BEGIN
                      RETURN p_CONTENT;
                  END;
              END;"
  );

  $self->do(
    "CREATE OR REPLACE TYPE T_GROUP_CONCAT AS OBJECT 
               (  CLOB_CONTENT CLOB,
                  DELIMITER    VARCHAR2(256),
                  STATIC FUNCTION ODCIAGGREGATEINITIALIZE(
                      SCTX IN OUT NOCOPY T_GROUP_CONCAT)
                  RETURN NUMBER,
                  MEMBER FUNCTION ODCIAGGREGATEITERATE(
                      SELF IN OUT NOCOPY T_GROUP_CONCAT,
                      VALUE IN T_CLOB_DELIM) 
                  RETURN NUMBER,
                  MEMBER FUNCTION ODCIAGGREGATETERMINATE(
                      SELF IN T_GROUP_CONCAT,
                      RETURNVALUE OUT NOCOPY CLOB,
                      FLAGS       IN NUMBER)
                  RETURN NUMBER,
                  MEMBER FUNCTION ODCIAGGREGATEMERGE(
                      SELF IN OUT NOCOPY T_GROUP_CONCAT,
                      CTX2 IN T_GROUP_CONCAT) 
                  RETURN NUMBER);"
  );

  $self->do(
    "CREATE OR REPLACE TYPE BODY T_GROUP_CONCAT IS
                  STATIC FUNCTION ODCIAGGREGATEINITIALIZE(
                  SCTX IN OUT NOCOPY T_GROUP_CONCAT)
                  RETURN NUMBER IS
                  BEGIN
                      SCTX := T_GROUP_CONCAT(EMPTY_CLOB(), NULL);
                      DBMS_LOB.CREATETEMPORARY(SCTX.CLOB_CONTENT, TRUE);
                      RETURN ODCICONST.SUCCESS;
                  END;
                  MEMBER FUNCTION ODCIAGGREGATEITERATE(
                      SELF IN OUT NOCOPY T_GROUP_CONCAT,
                      VALUE IN T_CLOB_DELIM) 
                  RETURN NUMBER IS
                  BEGIN
                      SELF.DELIMITER := VALUE.P_DELIMITER;
                      DBMS_LOB.WRITEAPPEND(SELF.CLOB_CONTENT, 
                                           LENGTH(SELF.DELIMITER),
                                           SELF.DELIMITER);
                      DBMS_LOB.APPEND(SELF.CLOB_CONTENT, VALUE.P_CONTENT);
  
                      RETURN ODCICONST.SUCCESS;
                  END;
                  MEMBER FUNCTION ODCIAGGREGATETERMINATE(
                      SELF IN T_GROUP_CONCAT,
                      RETURNVALUE OUT NOCOPY CLOB,
                      FLAGS IN NUMBER) 
                  RETURN NUMBER IS
                  BEGIN
                      RETURNVALUE := RTRIM(LTRIM(SELF.CLOB_CONTENT, 
                                     SELF.DELIMITER), 
                                     SELF.DELIMITER);
                      RETURN ODCICONST.SUCCESS;
                  END;
                  MEMBER FUNCTION ODCIAGGREGATEMERGE(
                      SELF IN OUT NOCOPY T_GROUP_CONCAT,
                      CTX2 IN T_GROUP_CONCAT) 
                  RETURN NUMBER IS
                  BEGIN
                      DBMS_LOB.WRITEAPPEND(SELF.CLOB_CONTENT, 
                                           LENGTH(SELF.DELIMITER), 
                                           SELF.DELIMITER);
                      DBMS_LOB.APPEND(SELF.CLOB_CONTENT, CTX2.CLOB_CONTENT);
                      RETURN ODCICONST.SUCCESS;
                  END;
               END;"
  );

  # Create user-defined aggregate function group_concat
  $self->do(
    "CREATE OR REPLACE FUNCTION GROUP_CONCAT(P_INPUT T_CLOB_DELIM) 
               RETURN CLOB 
               DETERMINISTIC PARALLEL_ENABLE AGGREGATE USING T_GROUP_CONCAT;"
  );

  # Create a WORLD_LEXER named BZ_LEX for multilingual fulltext search
  my $lexer = $self->selectcol_arrayref(
    "SELECT pre_name FROM CTXSYS.CTX_PREFERENCES WHERE pre_name = ? AND
          pre_owner = ?", undef, 'BZ_LEX', uc(Bugzilla->localconfig->{db_user})
  );
  if (!@$lexer) {
    $self->do(
      "BEGIN CTX_DDL.CREATE_PREFERENCE
                        ('BZ_LEX', 'WORLD_LEXER'); END;"
    );
  }

  $self->SUPER::bz_setup_database(@_);

  my $sth = $self->prepare(
    "SELECT OBJECT_NAME FROM USER_OBJECTS WHERE OBJECT_NAME = ?");
  my @tables = $self->bz_table_list_real();

  foreach my $table (@tables) {
    my @columns = $self->bz_table_columns_real($table);
    foreach my $column (@columns) {
      my $def = $self->bz_column_info($table, $column);

      # bz_add_column() before Bugzilla 4.2.3 didn't handle primary keys
      # correctly (bug 731156). We have to add missing sequences and
      # triggers ourselves.
      if ($def->{TYPE} =~ /SERIAL/i) {
        my $sequence = "${table}_${column}_SEQ";
        my $exists   = $self->selectrow_array($sth, undef, $sequence);
        if (!$exists) {
          my @sql = $self->_get_create_seq_ddl($table, $column);
          $self->do($_) foreach @sql;
        }
      }

      if ($def->{REFERENCES}) {
        my $references = $def->{REFERENCES};
        my $update     = $references->{UPDATE} || 'CASCADE';
        my $to_table   = $references->{TABLE};
        my $to_column  = $references->{COLUMN};
        my $fk_name    = $self->_bz_schema->_get_fk_name($table, $column, $references);

        # bz_rename_table didn't rename the trigger correctly.
        if ($table eq 'bug_tag' && $to_table eq 'tags') {
          $to_table = 'tag';
        }
        if ($update =~ /CASCADE/i) {
          my $trigger_name  = uc($fk_name . "_UC");
          my $exist_trigger = $self->selectcol_arrayref($sth, undef, $trigger_name);
          if (@$exist_trigger) {
            $self->do("DROP TRIGGER $trigger_name");
          }

          my $tr_str
            = "CREATE OR REPLACE TRIGGER $trigger_name"
            . " AFTER UPDATE OF $to_column ON $to_table "
            . " REFERENCING "
            . " NEW AS NEW "
            . " OLD AS OLD "
            . " FOR EACH ROW "
            . " BEGIN "
            . "     UPDATE $table"
            . "        SET $column = :NEW.$to_column"
            . "      WHERE $column = :OLD.$to_column;"
            . " END $trigger_name;";
          $self->do($tr_str);
        }
      }
    }
  }

  # Drop the trigger which causes bug 541553
  my $trigger_name  = "PRODUCTS_MILESTONEURL";
  my $exist_trigger = $self->selectcol_arrayref($sth, undef, $trigger_name);
  if (@$exist_trigger) {
    $self->do("DROP TRIGGER $trigger_name");
  }
}

# These two methods have been copied from Bugzilla::DB::Schema::Oracle.
sub _get_create_seq_ddl {
  my ($self, $table, $column) = @_;

  my $seq_name = "${table}_${column}_SEQ";
  my $seq_sql  = "CREATE SEQUENCE $seq_name INCREMENT BY 1 START WITH 1 "
    . "NOMAXVALUE NOCYCLE NOCACHE";
  my $trigger_sql = $self->_get_create_trigger_ddl($table, $column, $seq_name);
  return ($seq_sql, $trigger_sql);
}

sub _get_create_trigger_ddl {
  my ($self, $table, $column, $seq_name) = @_;

  my $trigger_sql
    = "CREATE OR REPLACE TRIGGER ${table}_${column}_TR "
    . " BEFORE INSERT ON $table "
    . " FOR EACH ROW "
    . " BEGIN "
    . "   SELECT ${seq_name}.NEXTVAL "
    . "   INTO :NEW.$column FROM DUAL; " . " END;";
  return $trigger_sql;
}

############################################################################

package Bugzilla::DB::Oracle::st;

use 5.10.1;
use strict;
use warnings;

use parent -norequire, qw(DBI::st);

sub fetchrow_arrayref {
  my $self = shift;
  my $ref  = $self->SUPER::fetchrow_arrayref(@_);
  return undef if !defined $ref;
  Bugzilla::DB::Oracle::_fix_arrayref($ref);
  return $ref;
}

sub fetchrow_array {
  my $self = shift;
  if (wantarray) {
    my @row = $self->SUPER::fetchrow_array(@_);
    Bugzilla::DB::Oracle::_fix_arrayref(\@row);
    return @row;
  }
  else {
    my $row = $self->SUPER::fetchrow_array(@_);
    $row = Bugzilla::DB::Oracle::_fix_empty($row) if defined $row;
    return $row;
  }
}

sub fetchrow_hashref {
  my $self = shift;
  my $ref  = $self->SUPER::fetchrow_hashref(@_);
  return undef if !defined $ref;
  Bugzilla::DB::Oracle::_fix_hashref($ref);
  return $ref;
}

sub fetchall_arrayref {
  my $self = shift;
  my $ref  = $self->SUPER::fetchall_arrayref(@_);
  return undef if !defined $ref;
  foreach my $row (@$ref) {
    if (ref($row) eq 'ARRAY') {
      Bugzilla::DB::Oracle::_fix_arrayref($row);
    }
    elsif (ref($row) eq 'HASH') {
      Bugzilla::DB::Oracle::_fix_hashref($row);
    }
  }
  return $ref;
}

sub fetchall_hashref {
  my $self = shift;
  my $ref  = $self->SUPER::fetchall_hashref(@_);
  return undef if !defined $ref;
  foreach my $row (values %$ref) {
    Bugzilla::DB::Oracle::_fix_hashref($row);
  }
  return $ref;
}

sub fetch {
  my $self = shift;
  my $row  = $self->SUPER::fetch(@_);
  if ($row) {
    Bugzilla::DB::Oracle::_fix_arrayref($row);
  }
  return $row;
}
1;

=head1 B<Methods in need of POD>

=over

=item adjust_statement

=item bz_check_regexp

=item bz_drop_table

=item bz_explain

=item bz_last_key

=item bz_setup_database

=item bz_table_columns_real

=item bz_table_list_real

=item do

=item prepare

=item prepare_cached

=item quote_identifier

=item selectall_arrayref

=item selectall_hashref

=item selectcol_arrayref

=item selectrow_array

=item selectrow_arrayref

=item selectrow_hashref

=item sql_date_format

=item sql_date_math

=item sql_from_days

=item sql_fulltext_search

=item sql_group_concat

=item sql_in

=item sql_limit

=item sql_not_regexp

=item sql_position

=item sql_regexp

=item sql_string_concat

=item sql_to_days

=back
