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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