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Tony Bowden

NAME

Class::DBI::Cascade::None - Do nothing upon deletion

DESCRIPTION

This is a Cascading Delete strategy that will do nothing, leaving orphaned records behind.

It is the base class for most ofther Cascade strategies, and so provides several important methods:

CONSTRUCTOR

new

        my $strategy = Cascade::Class->new($Relationship);

This must be instantiated with a Class::DBI::Relationship object.

METHODS

foreign_for

        my $iterator = $strategy->foreign_for($obj);

This will return all the objects which are foreign to $obj across the relationship. It's a normal Class::DBI search you can get the results either as a list or as an iterator.

cascade

        $strategy->cascade($obj);

Cascade across the related objects to $obj.

WRITING NEW STRATEGIES

Creating a Cascade strategy should be fairly simple. You usually just need to inherit from here, and then supply a cascade() method that does the required thing with the results from foreign_for().

So, for example, Cascade::Delete is implemented simply as:

        package Class::DBI::Cascade::Delete;

        use base 'Class::DBI::Cascade::None';

        sub cascade {
                my ($self, $obj) = @_;
                $self->foreign_for($obj)->delete_all;
        }