Re: select + insert vs. insert and catching exception

wouldn't a sequence actually generate a problem of duplicates when not wanted. Say the PK is phone number. Then, using a sequence as the PK would require a UNIQUE index on the phone number causing more overhead. If you just begin with a solid design of PK/FK relationships then you can let the database do the work for you.

Kevin

"Richard Foote" <richard.foote_at_bigpond.com> wrote in message news:umDk9.40468$g9.116855_at_newsfeeds.bigpond.com...
> Hi Christopher,
>
> I'll go for option two. Avoids having to unnecessarily perform the select
> and access the index twice.
>
> I would also recommend the use of a sequence (if appropriate) to eliminate
> the potential duplicate key error.
>
> Cheers
>
> Richard
> "Christoph Seidel" <chris666.seidel_at_gmx.de> wrote in message
> news:amut5g$9edrd$1_at_ID-143718.news.dfncis.de...
> > what is better in respect of performance?
> >
> > select by primary key, if not found insert
> >
> > or
> >
> > insert and catch exception if primary key exists
> >
> > the table is quite small, less than 100 rows
> >
> >
>
>
Received on Thu Sep 26 2002 - 09:44:38 CDT