Re: Subquery not allowed here

From: Maxim Demenko <mdemenko_at_gmail.com>
Date: Tue, 30 Aug 2005 00:25:05 +0200
Message-ID: <df01vu$oqk$00$1@news.t-online.com>

mike schrieb:
> I have 2 tables and I want to make sure that a value from tableb is
> included in tablea before it is entered.
>
> tables defined as:
>
> create tablea as
> (
> SUPPLIER_ID INTEGER NOT NULL,
> SUPPLIER_NAME VARCHAR(50) NOT NULL,
> SUPPLIER_LOCATION VARCHAR(50) NOT NULL
> )
>
> create tableb
> (
> LDAP_UID VARCHAR(40) NOT NULL,
> ACCESS_ID INTEGER NOT NULL,
> LM_FLAG CHAR(1) NOT NULL,
> SUPPLIER_ID INTEGER
> )
>
> I can't use a reference from tableb to tablea because the supplier_id
> could be null in tableb, but nulls can not exist in tablea
>

But if you make a supplier_id in tableb not null, then foreign key should be sufficient.

Best regards

Maxim Received on Mon Aug 29 2005 - 17:25:05 CDT