DBIx::Class::Storage::DBI::MultiColumnIn - Storage component for RDBMS supporting multicolumn in clauses

DBIx-Class documentation Contained in the DBIx-Class distribution.

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NAME

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DBIx::Class::Storage::DBI::MultiColumnIn - Storage component for RDBMS supporting multicolumn in clauses

DESCRIPTION

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While ANSI SQL does not define a multicolumn in operator, many databases can in fact understand WHERE (cola, colb) IN ( SELECT subcol_a, subcol_b ... ) The storage class for any such RDBMS should inherit from this class, in order to dramatically speed up update/delete operations on joined multipk resultsets.

At this point the only overridden method is _multipk_update_delete()

AUTHORS

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See CONTRIBUTORS in DBIx::Class

LICENSE

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You may distribute this code under the same terms as Perl itself.

DBIx-Class documentation Contained in the DBIx-Class distribution. 
package DBIx::Class::Storage::DBI::MultiColumnIn;

use strict;
use warnings;

use base 'DBIx::Class::Storage::DBI';
use mro 'c3';


sub _multipk_update_delete {
  my $self = shift;
  my ($rs, $op, $values) = @_;

  my $rsrc = $rs->result_source;
  my @pcols = $rsrc->_pri_cols;
  my $attrs = $rs->_resolved_attrs;

  # naive check - this is an internal method after all, we should know what we are doing 
  $self->throw_exception ('Number of columns selected by supplied resultset does not match number of primary keys')
    if ( ref $attrs->{select} ne 'ARRAY' or @{$attrs->{select}} != @pcols );

  # This is hideously ugly, but SQLA does not understand multicol IN expressions
  my $sqla = $self->_sql_maker;
  my ($sql, @bind) = @${$rs->as_query};
  $sql = sprintf ('(%s) IN %s',   # the as_query stuff is already enclosed in ()s
    join (', ', map { $sqla->_quote ($_) } @pcols),
    $sql,
  );

  return $self->$op (
    $rsrc,
    $op eq 'update' ? $values : (),
    \[$sql, @bind],
  );

}


1;