> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
> Behalf Of Niall Smart
>
>
> CONSTRAINT TYPE_CD_OK CHECK (
> EXISTS (SELECT 1 FROM XREF WHERE
> XREF_GROUP = 'CUST_TYPE' AND
> XREF_CD = TYPE_CD)
> )
>
>
> > There seems to be more serious problems.
> > 1) The constraint is not only for the defined table but also
> for referenced
> > tables in the subquery.
>
> I don't understand what you mean -- the constraint only
> constrains 1 column in one table...
>
Doesn't the constraint mean that
for any row in table CUST,there *always* exist some rows in
the table XREF such that satisfies XREF_GROUP='CUST_TYPE'
AND XREF_CD=TYPE_CD ?
If all such rows are deleted from the table XREF,above condition
isn't satisfied any longer. So isn't the constraint for the table XREF
either ?
Regards.
Hiroshi Inoue
[EMAIL PROTECTED]
