Hi, im attepting to use the REF to link the ID of tYPE B to the ID of TYPE A as ref integrity check. can this be done at the domain level or must it be implemented at the table level? this is my imp although it doesnt work in 9.01. can anyone help?

CREATE TYPE A AS OBJECT (
ID INT)
REF (ID)
NOT FINAL,

CREATE TABLE AA OF A

CREATE TYPE B UNDER A AS OBJECT (
ID INT,
name VARCHAR2(12))
ID REF (A)
FINAL