add placeholder support detection for mssql through dbd::sybase

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

package DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server;

use strict;
use warnings;

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

sub _rebless {
  my $self = shift;
  my $dbh  = $self->_dbh;

  my ($placeholders_supported) = eval {
# There's also $dbh->{syb_dynamic_supported} but it can be inaccurate for this
# purpose.
    local $dbh->{PrintError} = 0;
    $dbh->selectrow_array('select ?', {}, 1);
  };

  if (not $placeholders_supported) {
    bless $self,
      'DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server::NoBindVars';
    $self->_rebless;
  }

# LongReadLen doesn't work with MSSQL through DBD::Sybase, and the default is
# huge on some versions of SQL server and can cause memory problems, so we
# fix it up here.
  my $text_size = eval { $self->_dbi_connect_info->[-1]->{LongReadLen} } ||
    32768; # the DBD::Sybase default

  $dbh->do("set textsize $text_size");
}

1;

=head1 NAME

DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server - Support for Microsoft
SQL Server via DBD::Sybase

=head1 SYNOPSIS

This subclass supports MSSQL server connections via L<DBD::Sybase>.

=head1 DESCRIPTION

This driver tries to determine whether your version of L<DBD::Sybase> and
supporting libraries (usually FreeTDS) support using placeholders, if not the
storage will be reblessed to
L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server::NoBindVars>.

The MSSQL specific functionality is provided by
L<DBIx::Class::Storage::DBI::MSSQL>.

=head1 AUTHOR

See L<DBIx::Class/CONTRIBUTORS>.

=head1 LICENSE

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

=cut