Re: How do FKs work?

On Sat, 9 Oct 2004, Tom Lane wrote:

> "Marc G. Fournier" <scrappy@hub.org> writes:
>> Have a table with two FKs on it ... 2 different fields in the table point
>> to the same field in another table ...
>
>> When I do an 'EXPLAIN ANALYZE DELETE FROM table WHERE field = #;', it
>> never comes back ... or, at lesat, takes a *very* long time ...
>
> Do you have indexes on the referencing columns?  Are they exactly the
> same datatype as the referenced column?  You can get really awful plans
> for the FK-checking queries if not.

Yup, that was my first thought ... running SELECT's joining the two tables 
on the FK fields shows indices being used, and fast times ...

----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy@hub.org           Yahoo!: yscrappy              ICQ: 7615664