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Alzabo::Create::ForeigUser(Contributed Perl DocumAlzabo::Create::ForeignKey(3)

NAME
       Alzabo::Create::ForeignKey - Foreign key	objects	for schema creation.

SYNOPSIS
	 use Alzabo::Create::ForeignKey;

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.

INHERITS FROM
       "Alzabo::ForeignKey"

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

METHODS
   new
       The constructor takes the following parameters:

       o   columns_from	=> "Alzabo::Create::Column" object(s)

       o   columns_to => "Alzabo::Create::Column" object(s)

	   These two parameters	may be either a	single column or a reference
	   to an array columns.	 The number of columns in the two parameters
	   must	match.

       o   cardinality => [1, 1], [1, 'n'], or ['n', 1]

       o   from_is_dependent =>	$boolean

       o   to_is_dependent => $boolean

       o   comment => $comment

	   An optional comment.

       It returns a new	"Alzabo::Create::ForeignKey" object.

       Throws: "Alzabo::Exception::Params"

   table_from
   table_to
       Returns the relevant "Alzabo::Create::Table" object.

   columns_from
   columns_to
       Returns the relevant "Alzabo::Create::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::Create::Column" objects.  These two columns
       correspond in the tables	being linked together.

   set_columns_from ("Alzabo::Create::Column" object(s))
       Sets the	column(s) that the relation is from.  This can be either a
       single column object or a reference to an array of column objects.

       Throws: "Alzabo::Exception::Params"

   set_columns_to ("Alzabo::Create::Column" object(s))
       Sets the	column(s) that the relation is to.  This can be	either a
       single column object or a reference to an array of column objects.

       Throws: "Alzabo::Exception::Params"

   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.

   set_cardinality (\@cardinality) see above for details
       Sets the	cardinality of the foreign key.

       Throws: "Alzabo::Exception::Params"

   set_from_is_dependent ($boolean)
       Indicates whether or not	the first table	in the foreign key is
       dependent on the	other (i.e. whether the	'from' table is	dependent on
       the 'to'	table).

   set_to_is_dependent ($boolean)
       Indicates whether or not	the second table in the	foreign	key is
       dependent on the	other (i.e. whether the	'to' table is dependent	on the
       'from' table).

   id
       Returns a string	uniquely identifying the foreign key.

   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.

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

   set_comment ($comment)
       Sets the	comment	for the	foreign	key object.

AUTHOR
       Dave Rolsky, <autarch@urth.org>

perl v5.24.1			  2017-07-02	 Alzabo::Create::ForeignKey(3)

NAME | SYNOPSIS | DESCRIPTION | INHERITS FROM | METHODS | AUTHOR

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