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

mitt 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,...
> 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!

Given that foreign keys must be to either a primary key or unique constraint. And given that both of these constraints build an index by default ... how could you not have an index on the column in the parent table?

--
Daniel Morgan
http://www.outreach.washington.edu/extinfo/certprog/oad/oad_crs.asp
http://www.outreach.washington.edu/extinfo/certprog/aoa/aoa_main.asp
damorgan_at_x.washington.edu
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