Martijn Tonies wrote:

> > for the check of the primary key
>
> A Primary Key constraint.
>
> >, and the foreign key?, what is
>
> A Foreign Key constraint.
>
> > better?, declare it trought constraints?, or do trought declare
> > triggers that do the job?.
>
> No, I would throw triggers out of the window any day for this.
> http://www.cvalde.net/document/declaRefIntegVsTrig.htm

I agree with this entirely but... there was some discussion a year or
two back that FK's with low selectivity could affect performance (FB1)
and that this would not be an issue if the creation of an index on FK's
was made optional. In the meantime it was recommended (by Helen IIRC)
that in this situation it might be preferable to implement RI through
triggers rather than FK constraints.

Is this still recommended with FB1 - or have I misunderstood the advice?

Ray