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

NAME

       Alzabo::ForeignKey - Foreign key (relation) objects

SYNOPSIS

	 use Alzabo::ForeignKey;

	 foreach my $fk ($table->foreign_keys)
	 {
	     print $fk->cardinality;
	 }

DESCRIPTION

       A foreign key is an object defined by several properties.  It represents a relationship from a column or columns in one table to a column
       or columns in another table.

       This relationship is defined by its cardinality (one to one, one to many, or many to one) and its dependencies (whether or not table X is
       dependent on table Y, and vice versa).

       Many to many relationships are not allowed.  However, you may indicate such a relationship when using the Alzabo::Create::Schema->add_rela-
       tion method method, and it will create the necessary intermediate linking table for you.

METHODS

       table_from

       table_to

       Returns the relevant "Alzabo::Table" object.

       columns_from

       columns_to

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

       column_pairs

       Returns an array of array references.  The references are to two column array of "Alzabo::Column" objects.  These two columns correspond in
       the tables being linked together.

       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.

       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::ForeignKey(3pm)