How can I use REF to reference row objects?

I have two entities, Customer and Order, both of which I have created types for. The SQL type declarations are:

CREATE OR REPLACE TYPE  "CUSTOMERTYPE" AS OBJECT (
customerId CHAR(6),
name VARCHAR2(50),
address VARCHAR2(255),
telephone CHAR(11)
);

CREATE OR REPLACE TYPE  "ORDERTYPE" AS OBJECT (
customer REF CustomerType,
orderId CHAR(10),
orderDate DATE,
totalCost FLOAT
);

The idea being that a customer can place 1..* orders. An order is placed by 1..1 customer.

I've also created CustomerTable and OrderTable tables like so:

CREATE TABLE  "CUSTOMERTABLE" OF  "CUSTOMERTYPE";
CREATE TABLE  "ORDERTABLE" OF  "ORDERTYPE";

There is an entry in CustomerTable with customerId = '123456'. When I execute the following:

INSERT INTO OrderTable
  SELECT OrderType (REF(c), '1234567890', '02-Nov-2009', 99)
    FROM CustomerTable c
    WHERE c.customerId = '123456';

Oracle rep开发者_运维技巧orts that the row has been inserted. However, when I check the data I get error:

ORA-00932: inconsistent datatypes: expected NUMBER got REF MILKPLUSVELLOCET.CUSTOMERTYPE

Any help would be greatly appreciated.

What do you mean by 'when I check the data'?

This works on my machine:

declare
  cust customertype;
begin
  cust := new customertype('111111', 'Mr. Burns', '42 Mil,ky Way', '+41 75 000');
  insert into customertable values cust;
end;
/


INSERT INTO OrderTable
  SELECT OrderType (REF(c), '1234567890', '02-Nov-2009', 99)
      FROM CustomerTable c
          WHERE c.customerId = '111111';

--

select * from ordertable;

select o.customer.name from ordertable o where o.orderid = '1234567890';