Re: Column 'CHECK' Constraint: bug or ?

On Wed, 19 Sep 2001, Keary Suska wrote:

> It appears that Postgres checks column CHECK constraints when performing an
> update regardless of whether the particular column is being updated. Perhaps
> my understanding of column vs table constraints is incomplete but this
> doesn't seem to be proper behavior, and I can't find it documented anywhere.

If I read spec correctly, a column check constraint is equivalent to a
table constraint of the same search condition (and name and
attributes) for purposes of checking the constraint which means it should
be valid at end of transaction/statement depending on the constraint
attributes (and we don't support deferred check right now).