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Alzabo::ForeignKey(3pm) | User Contributed Perl Documentation | Alzabo::ForeignKey(3pm) |
NAME¶
Alzabo::ForeignKey - Foreign key (relation) objectsSYNOPSIS¶
use Alzabo::ForeignKey; foreach my $fk ($table->foreign_keys) { print $fk->cardinality; }
DESCRIPTION¶
A foreign key is an object defined by several properties. It represents a relationship from a column or columns in one table to a column or columns in another table.This relationship is defined by its cardinality (one to one, one to many, or many to one) and its dependencies (whether or not table X is dependent on table Y, and vice versa).
Many to many relationships are not allowed. However, you may indicate such a relationship when using the Alzabo::Create::Schema->add_relation method method, and it will create the necessary intermediate linking table for you.
METHODS¶
table_from¶
table_to¶
Returns the relevant "Alzabo::Table" object.columns_from¶
columns_to¶
Returns the relevant "Alzabo::Column" object(s) for the property as an array.column_pairs¶
Returns an array of array references. The references are to two column array of "Alzabo::Column" objects. These two columns correspond in the tables being linked together.cardinality¶
Returns a two element array containing the two portions of the cardinality of the relationship. Each portion will be either '1' or 'n'.from_is_dependent¶
to_is_dependent¶
Returns a boolean value indicating whether there is a dependency from one table to the other.is_one_to_one¶
is_one_to_many¶
is_many_to_one¶
Returns a boolean value indicating what kind of relationship the object represents.is_same_relationship_as ($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>2015-05-24 | perl v5.20.2 |