Martijn Tonies wrote:

>
>>
>>...If constraints are restricted to the current row and constant
>>values, the transaction context is irrelevant. If, on the other hand,
>>a constraint can reference other rows in the current table or rows from
>>other tables, the transaction context is critical.
>>... More recent versions of the spec seem to allow references
>>outside the current row - a useful feature, one might think.
>
> If it were enforced at all times, yes. But I believe we agreed that our
> CHECK constraints (from a domain or table) are not enforced at
> all times, but only at INSERT or UPDATE. This makes it somewhat
> less useful.

Right. We need a mechanism to check constraints on changes to the
referenced tables as well as changes to the table constrained. Not
impossible, but different. At the moment, cross-table constraints
have two separate faults ...


Regards,


Ann