add manual descriptions

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / Manual / Cookbook.pod

=head1 NAME 

DBIx::Class::Manual::Cookbook - Misc receipes

=over 4

=item Input validation.

=item Using joins

=item Many-to-many relationships

This is not as easy as it could be, but it's possible. Here's an example to 
illustrate:

    package Base; 

    use base qw/DBIx::Class/;

    __PACKAGE__->load_components(qw/Core DB/);
    __PACKAGE__->connection(...);

    package Left;

    use base qw/Base/;

    __PACKAGE__->table('left');
    __PACKAGE__->add_columns(qw/id left_stuff/);
    __PACKAGE__->set_primary_key(qw/id/);
    __PACKAGE__->has_many('mid' => 'Mid');

    sub right {
     my ($self) = @_;
     return Right->search(
       { 'left.id' => $self->id },
       { join => { 'mid' => 'left' }});
    }

    package Mid;

    use base qw/Base/;

    __PACKAGE__->table('mid');
    __PACKAGE__->add_columns(qw/left right/);
    __PACKAGE__->set_primary_key(qw/left right/);

    __PACKAGE__->belongs_to('left' => 'Left');
    __PACKAGE__->belongs_to('right' => 'Right');

    package Right;

    use base qw/Base/;

    __PACKAGE__->table('right');
    __PACKAGE__->add_columns(qw/id right_stuff/);
    __PACKAGE__->set_primary_key(qw/id/);
    __PACKAGE__->has_many('mid' => 'Mid');

    sub left {
     my ($self) = @_;
     return Left->search(
       { 'right.id' => $self->id },
       { join => { 'mid' => 'right' });
    }

=item Advanced Exception handling

=item Transactions

=back