Re: constraint modification on todo list

Tom Lane wrote:
> Jeroen Ruigrok/asmodai <asmodai@wxs.nl> writes:
> > can someone add:
> > Add an ALTER TABLE MODIFY CONSTRAINT
> > item to the todo list?
> 
> Why?  For a constraint, it's not obvious what this would do for you that
> dropping and re-adding the constraint wouldn't do.  In the places where
> we support CREATE OR REPLACE, it's because it's important to maintain
> continuity of the object's identity, but I don't see any need for that
> with respect to check constraints.

I assume MODIFY would allow you to alter the constraint without
re-checking all the rows, as would be required by DROP/ADD.  However, if
you are modifying the constraint, wouldn't we have to recheck all the
rows anyway.  Of course, one idea would be to allow MODIFY to make
changes that _don't_ require rechecking, but I have no idea what such
changes would be.

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