Alzabo::Runtime::ForeignKey(3pm)			User Contributed Perl Documentation			  Alzabo::Runtime::ForeignKey(3pm)

NAME

       Alzabo::Runtime::ForeignKey - Foreign key objects

SYNOPSIS

	 $fk->register_insert( $value_for_column );
	 $fk->register_update( $new_value_for_column );
	 $fk->register_delete( $row_being_deleted );

DESCRIPTION

       Objects in this class maintain referential integrity.  This is really only useful when your RDBMS can't do this itself (like MySQL without
       InnoDB).

INHERITS FROM

       "Alzabo::ForeignKey"

       Note: all relevant documentation from the superclass has been merged into this document.

METHODS

       table_from

       table_to

       Returns the relevant "Alzabo::Runtime::Table" object.

       columns_from

       columns_to

       Returns the relevant "Alzabo::Runtime::Column" object(s) for the property as an array.

       cardinality

       Returns a two element array containing the two portions of the cardinality of the relationship.	Each portion will be either '1' or 'n'.

       from_is_dependent

       to_is_dependent

       Returns a boolean value indicating whether there is a dependency from one table to the other.

       is_one_to_one

       is_one_to_many

       is_many_to_one

       Returns a boolean value indicating what kind of relationship the object represents.

       is_same_relationship_as ($fk)

       Given a foreign key object, this returns true if the two objects represent the same relationship.  However, the two objects may represent
       the same relationship from different table's points of view.

       register_insert ($new_value)

       This method takes the proposed column value for a new row and makes sure that it is valid based on relationship that this object repre-
       sents.

       Throws: "Alzabo::Exception::ReferentialIntegrity"

       register_update ($new_value)

       This method takes the proposed new value for a column and makes sure that it is valid based on relationship that this object represents.

       Throws: "Alzabo::Exception::ReferentialIntegrity"

       register_delete ("Alzabo::Runtime::Row" object)

       Allows the foreign key to delete rows dependent on the row being deleted.  Note, this can lead to a chain reaction of cascading deletions.
       You have been warned.

       Throws: "Alzabo::Exception::ReferentialIntegrity"

       id

       Returns a string uniquely identifying the foreign key.

       comment

       Returns the comment associated with the foreign key object, if any.

AUTHOR

       Dave Rolsky, <autarch@urth.org>

perl v5.8.8							    2007-12-23					  Alzabo::Runtime::ForeignKey(3pm)