Clarification to cascade_update attribute documentation

[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 17de514..b4984e7 100644 (file)
--- a/lib/DBIx/Class/Relationship/Base.pm
+++ b/lib/DBIx/Class/Relationship/Base.pm
@@ -122,6 +122,37 @@ 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 cascade_copy
+
+If C<cascade_copy> is true on a C<has_many> relationship for an
+object, then when you copy the object all the related objects will
+be copied too. To turn this behaviour off, pass C<< cascade_copy => 0 >> 
+in the C<$attr> hashref. The behaviour defaults to C<< cascade_copy => 1 >>.
+
+=item cascade_delete
+
+By default, DBIx::Class cascades deletes across C<has_many> and
+C<might_have> relationships. You can disable this behaviour on a
+per-relationship basis by supplying C<< cascade_delete => 0 >> in the
+relationship attributes.
+
+The cascaded operations are performed after the requested delete,
+so if your database has a constraint on the relationship, it will
+have deleted/updated the related records or raised an exception
+before DBIx::Class gets to perform the cascaded operation.
+
+=item cascade_update
+
+By default, DBIx::Class cascades updates across C<has_many> and
+C<might_have> relationships. You can disable this behaviour on a
+per-relationship basis by supplying C<< cascade_update => 0 >> in the
+relationship attributes.
+
+This is not a RDMS style cascade update - it purely means that when
+an object has update called on it, all the related objects also
+have update called. It will not change foreign keys automatically -
+you must arrange to do this yourself.
+
 =item on_delete / on_update
 
 If you are using L<SQL::Translator> to create SQL for you, you can use these
@@ -200,9 +231,19 @@ sub related_resultset {
     my $query = ((@_ > 1) ? {@_} : shift);
 
     my $source = $self->result_source;
-    my $cond = $source->_resolve_condition(
-      $rel_info->{cond}, $rel, $self
-    );
+
+    # condition resolution may fail if an incomplete master-object prefetch
+    # is encountered - that is ok during prefetch construction (not yet in_storage)
+    my $cond = eval { $source->_resolve_condition( $rel_info->{cond}, $rel, $self ) };
+    if (my $err = $@) {
+      if ($self->in_storage) {
+        $self->throw_exception ($err);
+      }
+      else {
+        $cond = $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION;
+      }
+    }
+
     if ($cond eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
       my $reverse = $source->reverse_relationship_info($rel);
       foreach my $rev_rel (keys %$reverse) {