Re: FK v.s unique indexes

On Tuesday, July 3, 2018, Rafal Pietrak <rafal(at)ztk-rp(dot)eu> wrote:

>
> ERROR: there is no unique constraint matching given keys for referenced
> table "test2"
> ----------------------------
>
> I cannot see any reasons why this functionality is blocked.
>
> In particular, contrary to what the ERROR says, the target table *does
> have* a "unique constraint matching given keys", admittedly only
> partial.
>

You are making the common error of confusing the distinct concepts of
constraints and indexs. Table constraints cannot be partial by definition,
and are a logical concept constraining the data model. Indexes are
physical objects that only aid in the execution of queries. The only
crossover is that the implementation of a unique table constraint uses a
full unique index as an implementation detail.

The error says 'constraint' and indeed you have nit defined a relevant
constraint in your schema, just indexes.

David J.