Re: [SQL] Staus of Primary/Foreign key?

> >
> > I have implemented referential integrity in older Postgres projects
> > using functions. I am preparing to do a new project, aand was wondering
> > what the status of Primary/Foreign key implementation was?
> >
> > I am starting with 6.4.2,
>
> I'm planning to implement most of the constraints currently
> missing (foreign key, cascaded deletes) over rules - or at
> least making the rule system capable of supporting it.
>
> But it will not be in v6.5. The reason for that is that
> constraints need a special feature, the rule system currently
> cannot support. It is required that rule actions can be
> deferred until transaction commit time. At that time (or
> when they should get run anyway), they need very special
> visibility of heap tuples on a per range table base. One and
> the same table might have to be scanned with different
> snapshot's in one query.
>
> That all will take a while.

I am glad to hear Jan say this. I hoped he had not given up on the idea
of doing foreign keys. This is a major feature people are requesting.

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