remove (groditi) instances

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / ResultSource / View.pm

package DBIx::Class::ResultSource::View;

use strict;
use warnings;

use DBIx::Class::ResultSet;

use base qw/DBIx::Class/;
__PACKAGE__->load_components(qw/ResultSource/);
__PACKAGE__->mk_group_accessors(
  'simple' => qw(is_virtual view_definition)
);

=head1 NAME

DBIx::Class::ResultSource::View - ResultSource object representing a view

=head1 SYNOPSIS

  package MyDB::Schema::Year2000CDs;

  use DBIx::Class::ResultSource::View;

  __PACKAGE__->load_components('Core');
  __PACKAGE__->table_class('DBIx::Class::ResultSource::View');

  __PACKAGE__->table('year2000cds');
  __PACKAGE__->result_source_instance->is_virtual(1);
  __PACKAGE__->result_source_instance->view_definition(
      "SELECT cdid, artist, title FROM cd WHERE year ='2000'"
      );

=head1 DESCRIPTION

View object that inherits from L<DBIx::Class::ResultSource>

This class extends ResultSource to add basic view support. 

A view has a L</view_definition>, which contains an SQL query. The
query cannot have parameters. It may contain JOINs, sub selects and
any other SQL your database supports.

View definition SQL is deployed to your database on
L<DBIx::Class::Schema/deploy> unless you set L</is_virtual> to true.

Deploying the view does B<not> translate it between different database
syntaxes, so be careful what you write in your view SQL.

Virtual views (L</is_virtual> unset or false), are assumed to not
exist in your database as a real view. The L</view_definition> in this
case replaces the view name in a FROM clause in a subselect.

=head1 SQL EXAMPLES

=over

=item is_virtual set to true

  $schema->resultset('Year2000CDs')->all();

  SELECT cdid, artist, title FROM year2000cds me

=item is_virtual set to false

  $schema->resultset('Year2000CDs')->all();

  SELECT cdid, artist, title FROM 
    (SELECT cdid, artist, title FROM cd WHERE year ='2000') me

=back

=head1 METHODS

=head2 is_virtual

  __PACKAGE__->result_source_instance->is_virtual(1);

Set to true for a virtual view, false or unset for a real
database-based view.

=head2 view_definition

  __PACKAGE__->result_source_instance->view_definition(
      "SELECT cdid, artist, title FROM cd WHERE year ='2000'"
      );

An SQL query for your view. Will not be translated across database
syntaxes.


=head1 OVERRIDDEN METHODS

=head2 from

Returns the FROM entry for the table (i.e. the view name)
or the SQL as a subselect if this is a virtual view.

=cut

sub from {
  my $self = shift;
  return \"(${\$self->view_definition})" if $self->is_virtual;
  return $self->name;
}

1;

=head1 AUTHORS

Matt S. Trout <mst@shadowcatsystems.co.uk>

With Contributions from:

Guillermo Roditi E<lt>groditi@cpan.orgE<gt>

Jess Robinson <castaway@desert-island.me.uk>

=head1 LICENSE

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

=cut