- Allow explicit specification of ON DELETE/ON UPDATE constraints when using the...

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / Relationship / Base.pm

diff --git a/lib/DBIx/Class/Relationship/Base.pm b/lib/DBIx/Class/Relationship/Base.pm
index b8f2467..72ac9f0 100644 (file)
--- a/lib/DBIx/Class/Relationship/Base.pm
+++ b/lib/DBIx/Class/Relationship/Base.pm
@@ -109,6 +109,19 @@ is creating constraints where it shouldn't, or not creating them where it
 should, set this attribute to a true or false value to override the detection
 of when to create constraints.
 
+=item on_delete / on_update
+
+If you are using L<SQL::Translator> to create SQL for you, you can use these
+attributes to explicitly set the desired C<ON DELETE> or C<ON UPDATE> constraint 
+type. If not supplied the SQLT parser will attempt to infer the constraint type by 
+interrogating the attributes of the B<opposite> relationship. For any 'multi'
+relationship with C<< cascade_delete => 1 >>, the corresponding belongs_to 
+relationship will be created with an C<ON DELETE CASCADE> constraint. For any 
+relationship bearing C<< cascade_copy => 1 >> the resulting belongs_to constraint
+will be C<ON UPDATE CASCADE>. If you wish to disable this autodetection, and just
+use the RDBMS' default constraint type, pass C<< on_delete => undef >> or 
+C<< on_delete => '' >>, and the same for C<on_update> respectively.
+
 =item is_deferrable
 
 Tells L<SQL::Translator> that the foreign key constraint it creates should be