"Joris Dobbelsteen" <Joris@familiedobbelsteen.nl> writes:
> I have some trouble guarenteeing that an ordering constraint is enforced
> on the database. On the table ordering (see below) I want to enforce
> that for every tuple t, all tuples u where u.position < t.position this
> implies u.cumvalue <= t.cumvalue.
I can't think of any reasonable way to enforce that in SQL. Perhaps you
should consider restructuring your tables in such a way that this
behavior emerges from a constraint that is enforceable --- maybe the
cumulative values should be a (materialized?) view on an underlying
table that contains individual observations.
regards, tom lane