rename method and add docs

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / Storage / DBI / AutoCast.pm

package DBIx::Class::Storage::DBI::AutoCast;

use strict;
use warnings;

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

__PACKAGE__->mk_group_accessors('simple' => 'auto_cast' );

=head1 NAME

DBIx::Class::Storage::DBI::AutoCast

=head1 SYNOPSIS

  $schema->storage->auto_cast(1);

=head1 DESCRIPTION

In some combinations of RDBMS and DBD drivers (e.g. FreeTDS and Sybase)
statements with values bound to columns or conditions that are not strings will
throw implicit type conversion errors.

As long as a column L<data_type|DBIx::Class::ResultSource/add_columns> is
defined, and it resolves to a base RDBMS native type via L</_map_data_type> as
defined in your Storage driver, the placeholder for this column will be
converted to:

  CAST(? as $mapped_type)

=cut

sub _prep_for_execute {
  my $self = shift;
  my ($op, $extra_bind, $ident, $args) = @_;

  my ($sql, $bind) = $self->next::method (@_);

# If we're using ::NoBindVars, there are no binds by this point so this code
# gets skippeed.
  if ($self->auto_cast && @$bind) {
    my $new_sql;
    my @sql_part = split /\?/, $sql;
    my $col_info = $self->_resolve_column_info($ident,[ map $_->[0], @$bind ]);

    foreach my $bound (@$bind) {
      my $col = $bound->[0];
      my $type = $self->_map_data_type($col_info->{$col}{data_type});

      foreach my $data (@{$bound}[1..$#$bound]) {   # <--- this will multiply the amount of ?'s no...?
        $new_sql .= shift(@sql_part) .
          ($type ? "CAST(? AS $type)" : '?');
      }
    }
    $new_sql .= join '', @sql_part;
    $sql = $new_sql;
  }

  return ($sql, $bind);
}


=head1 AUTHORS

See L<DBIx::Class/CONTRIBUTORS>

=head1 LICENSE

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

=cut

1;