Re: Indexes

From: Michael Serbanescu <mserban_at_postoffice.worldnet.att.net>
Date: 1997/07/22
Message-ID: <33D58C88.5C94@postoffice.worldnet.att.net>#1/1

You cannot create a UNIQUE index which ORACLE uses to enforce a PRIMARY KEY constraint if any of the columns in the constraint is optional; in all other situations, a non-unique or unique index will work on an optional column.

Hope this helps.

Michael Serbanescu

---

Brad Worsfold wrote:
>
> Hello.
>
> If I want to create a composite index on two columns, will Oracle Index a
> row if one
> of the columns is optional? Meaning that one column has a value, the other
> is null???
>
> I was told that Indexes are not created on rows with Null Values?
>
> If this is true, then it would be better not to index that table, right???
>
> I hope to hear something back????
>
> Thanks.
>
> Brad Worsfold
  Received on Tue Jul 22 1997 - 00:00:00 CDT