--
-- content_type__unregister_child_type/3
--
create or replace function content_type__unregister_child_type(
  character varying,
  character varying,
  character varying
) returns int4 as $$

declare
  unregister_child_type__parent_type            alias for $1;  
  unregister_child_type__child_type             alias for $2;  
  unregister_child_type__relation_tag           alias for $3;  -- default null
begin

  delete from 
    cr_type_children
  where 
    parent_type = unregister_child_type__parent_type
  and 
    child_type = unregister_child_type__child_type
  and
    relation_tag = unregister_child_type__relation_tag;

  return 0; 
end;$$ language plpgsql;