Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> comp.databases.theory -> Re: Requirements for update languages?

Re: Requirements for update languages?

From: Lauri Pietarinen <lauri.pietarinen_at_atbusiness.com>
Date: 12 Nov 2002 23:59:11 -0800
Message-ID: <e9d83568.0211122359.4cf1d6c6@posting.google.com>


> Is there a typo in your example -- missing quantities. Also you need a
> "distinct" keyword whenever referring to sets. Also it seems that the
> table of integers is unnecessary:
>
> SQL>select distinct C1, C2, T1.Q * T2.Q from
> 2 (select 0 C1, 2 Q from dual) T1,
> 3 (select 1 C2, 1 Q from dual
> 4 union
> 5 select 2 C2, 1 Q from dual) T2
>
> C1 C2 T1.Q*T2.Q
> ---------- ---------- ----------
> 0 1 2
> 0 2 2

OK, right. My point being that we have now converted the bags into sets, so Date's claim...

"If you do try this exercise, I believe you'll find you're inevitably led into using the language of sets, not bags, in order to get around the errors and ambiguities."

...stands true.

regards,
Lauri Pietarinen Received on Wed Nov 13 2002 - 01:59:11 CST

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US