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

NAME  DESCRIPTION  CONSTRUCTOR  new  METHODS  foreign_for  cascade  WRITING NEW STRATEGIES 

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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;
}

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