delete from doc_tree where id= 12 ;

ERROR:  колонка "id_low" не существует
СТРОКА 1:delete from doc_gen where id_low= $1 
                                ^
ЗАПРОС:  delete from doc_gen where id_low= $1 
КОНТЕКСТ:  PL/pgSQL function "del_doc_tree_record" line 2 at SQL statement

CREATE OR REPLACE FUNCTION del_doc_tree_record()
RETURNS opaque AS $$
BEGIN
  delete from doc_gen where id_low=OLD.id;  
END;
$$ LANGUAGE 'plpgsql';

CREATE TRIGGER del_doc_tree_record_trig
BEFORE DELETE
 ON doc_tree FOR EACH ROW
 EXECUTE PROCEDURE del_doc_tree_record();

  delete from doc_gen where [FIXED]id_low=OLD.id[/FIXED];  
                                                  ^^^ Как указать?