Re: Strange contraint help please...
Date: 29 Nov 2001 17:15:57 -0500
Message-ID: <87zo55fcki.fsf_at_mobile.follmann-net>
harry <a_at_abc.com> writes:
> Using Oracle 8i on win NT 4 server(sp6a)
>
> How can I get around this problem? - I have 3 tables with one column each -
>
> A
> =
> ID number(8)
>
> B
> =
> ID number(8)
>
> C
> =
> ID number(8)
>
>
> containin data
>
> A
> =
> 1
> 2
> 3
>
> C
> =
> 4
> 5
> 6
>
> B
> =
> 1
> 2
> 3
> 4
> 5
> 6
>
> how can I add a referential integrity constraints to table B that ensures
> the values exist in tables
> A OR C ?
>
> This code below fails as 4,5,6 are in table B -
>
> ALTER TABLE b ADD CONSTRAINT A_FK
> FOREIGN KEY (ID)
> REFERENCES a (ID) ;
>
>
> Any ideas?
>
> thanks
>
> harry
The database cannot do it because your integrity is already broken. first you have to create a status which complies to the constraints you want to enforce.
Not to mention of course you reference has to be uniquely indexed.
Cheers,
Henning
-- Henning Follmann | H.Follmann_at_gmx.de 8 Jane Road | (+1)(908) 464 8972 New Providence, NJ 07974 | USA -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! Check out our new Unlimited Server. No Download or Time Limits! -----== Over 80,000 Newsgroups - 19 Different Servers! ==-----Received on Thu Nov 29 2001 - 23:15:57 CET