On Fri, 2005-03-25 at 10:17 -0500, Tom Lane wrote:
> Simon Riggs <simon@2ndquadrant.com> writes:
> > I vote to make this an ERROR in 8.1 - I see little benefit in allowing
> > this situation to continue.
>
> Other than spec compliance, you mean? SQL99 says
>
> ... The declared type of each referencing column shall be
> comparable to the declared type of the corresponding referenced
> column.
>
> It doesn't say that it has to be indexable, and most definitely not that
> there has to be an index.
specs at dawn, eh?
Well, SQL:2003 Foundation, p.550 clause 3a) states that the the
<reference columns> in the referencing table must match a unique
constraint on the referenced table, or the PRIMARY KEY if the columns
are not specified. Either way, the referenced columns are a unique
constraint (which makes perfect sense from a logical data perspective).
We implement unique constraints via an index, so for PostgreSQL the
clause implies that it must refer to an index.
touche, Monsieur Lane and Happy Easter :-)
But even without that, there is little benefit in allowing it...
WARNING -> ERROR, please.
Best Regards, Simon Riggs
