SQL & PL/SQL

Hi folks,

I have this situation.

SQL> ed
Wrote file afiedt.buf

  1* create table x (id varchar2(10))
SQL> /

Table created.

SQL> ED
Wrote file afiedt.buf

  1* create table y(name varchar2(10))
SQL> /

Table created.

SQL> insert into x values ('texas');

1 row created.

SQL> commit;

Commit complete.

SQL> alter table y add constraint rahul_check check(name in (select id from x));
alter table y add constraint rahul_check check(name in (select id from x))
                                                        *
ERROR at line 1:
ORA-02251: subquery not allowed here

I heard this can ONLY be implemented using a trigger, but, is there a way to do this using a 'check constraint'?

Thank you,
Rahul.