X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FTree%2FAdjacencyList.pm;h=a77eeda0f36f9c0a869bfe02fc9d7ca8cb0c0323;hb=refs%2Fheads%2Fmaster;hp=e14875fe3e53a3cca2e11ac000ca6a75184ccae1;hpb=ab184e4a4303cde87f3f585ec422f99898a915b4;p=dbsrgits%2FDBIx-Class-Tree.git

diff --git a/lib/DBIx/Class/Tree/AdjacencyList.pm b/lib/DBIx/Class/Tree/AdjacencyList.pm
index e14875f..a77eeda 100644
--- a/lib/DBIx/Class/Tree/AdjacencyList.pm
+++ b/lib/DBIx/Class/Tree/AdjacencyList.pm
@@ -66,7 +66,7 @@ stop you from having multiple root nodes.
   __PACKAGE__->parent_column('parent_id');
 
 Declares the name of the column that contains the self-referential
-ID which defines the parent row.  This will create a has_many (children) 
+ID which defines the parent row.  This will create a has_many (children)
 and belongs_to (parent) relationship.
 
 This method also sets up an additional has_many relationship called
@@ -362,6 +362,30 @@ sub set_primary_key {
 1;
 __END__
 
+=head1 CAVEATS
+
+=head2 Generated schemas
+
+If you are using L<DBIx::Class::Schema/deploy> methods either directly
+or via L<DBIx::Class::DeploymentHandler> or L<DBIx::Migration>, you
+will need the following L<SQL::Translator> hook to remove the constraint
+from C<parent_column>, otherwise you will not be able to user 0 (zero) as
+a value.
+
+  sub sqlt_deploy_hook {
+      my ($self, $sqlt_table) = @_;
+
+      foreach my $constraint ($sqlt_table->get_constraints) {
+          if ($constraint->field_names->[0] eq $self->parent_column) {
+              $sqlt_table->drop_constraint($constraint->name);
+              last;
+          }
+      }
+  }
+
+ALso see L<DBIx::Class::Manual::Cookbook/Adding Indexes And Functions To
+Your SQL> for other examples.
+
 =head1 INHERITED METHODS
 
 =head2 DBIx::Class