Merge 'trunk' into 'sybase'

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

package DBIx::Class::Storage::DBI::NoBindVars;

use strict;
use warnings;

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

=head1 NAME 

DBIx::Class::Storage::DBI::NoBindVars - Sometime DBDs have poor to no support for bind variables

=head1 DESCRIPTION

This class allows queries to work when the DBD or underlying library does not
support the usual C<?> placeholders, or at least doesn't support them very
well, as is the case with L<DBD::Sybase>

=head1 METHODS

=head2 connect_info

We can't cache very effectively without bind variables, so force the C<disable_sth_caching> setting to be turned on when the connect info is set.

=cut

sub connect_info {
    my $self = shift;
    my $retval = $self->next::method(@_);
    $self->disable_sth_caching(1);
    $retval;
}

=head2 _prep_for_execute

Manually subs in the values for the usual C<?> placeholders.

=cut

sub _prep_for_execute {
  my $self = shift;

  my ($op, $extra_bind, $ident, $args) = @_;

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

  # stringify args, quote via $dbh, and manually insert

  my @sql_part = split /\?/, $sql;
  my $new_sql;

  my $col_info = $self->_resolve_column_info($ident, [ map $_->[0], @$bind ]);

  foreach my $bound (@$bind) {
    my $col = shift @$bound;

    my $datatype = $col_info->{$col}{data_type};

    foreach my $data (@$bound) {
      $data = ''.$data if ref $data;

      $data = $self->transform_unbound_value($datatype, $data)
        if $datatype;

      $data = $self->_dbh->quote($data)
        if (!$datatype || $self->should_quote_value($datatype, $data));

      $new_sql .= shift(@sql_part) . $data;
    }
  }
  $new_sql .= join '', @sql_part;

  return ($new_sql, []);
}

=head2 should_quote_value

This method is called by L</_prep_for_execute> for every column in
order to determine if its value should be quoted or not. The arguments
are the current column data type and the actual bind value. The return
value is interpreted as: true - do quote, false - do not quote. You should
override this in you Storage::DBI::<database> subclass, if your RDBMS
does not like quotes around certain datatypes (e.g. Sybase and integer
columns). The default method always returns true (do quote).

 WARNING!!!                     

 Always validate that the bind-value is valid for the current datatype.
 Otherwise you may very well open the door to SQL injection attacks.

=cut                            

sub should_quote_value { 1 }

=head2 transform_unbound_value

Given a datatype and the value to be inserted directly into a SQL query, returns
the necessary SQL fragment to represent that value.

=cut

sub transform_unbound_value { $_[2] }

=head1 AUTHORS

Brandon Black <blblack@gmail.com>

Trym Skaar <trym@tryms.no>

=head1 LICENSE

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

=cut

1;