Re: [SOLVED for good] performance tuning questions: replace IN (values) by JOIN

mitt <nospam_at_nospam.at> wrote:
> tojo wrote:
> > In article <3f5315cd$0$10359$afc38c87_at_news.optusnet.com.au>,
> > howardjr2000_at_yahoo.com.au says...
> >
> > isn't there only a locking issue if you update the primary key of the
> > parent table? Updating other fields should be OK. Please correct me if
> > I'm wrong.
>
> and the same is true for deletes of parent-rows and inserts of
> child-rows,...

Why inserts of child-rows? I don't see how that would cause problems.

> the situations in which it is not necessary to have an index on a
> foreign key are so rare in real life, it easiest not to think much and
> just create one!

Yes, I think that even with locking issues aside, it's hard to imagine a child table where you wouldn't want to look things up in such a way that it would benefit from the index. I guess maybe if it's a "write only" table except for massive EOM or EOY reports.

Xho

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