Re: constraint modification on todo list

-On [20030908 22:42], Bruce Momjian (pgman(at)candle(dot)pha(dot)pa(dot)us) wrote:
>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.

I might have misread/misremembered something:

Constraint State Modification

You can use the MODIFY CONSTRAINT clause of the ALTER TABLE statement to
change the following constraint states:

* DEFERRABLE or NOT DEFERRABLE
* INITIALLY DEFERRED or INITIALLY IMMEDIATE
* RELY or NORELY
* USING INDEX ...
* ENABLE or DISABLE
* VALIDATE or NOVALIDATE
* EXCEPTIONS INTO ...

http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96540/statements_32a.htm#2103836

I wonder if it is possible to have ALTER TABLE ... MODIFY CONSTRAINT ...
CHECK ...
Because what I can imagine, and please correct me if I miss something in
my thought pattern, you have a small gap between dropping a constraint
and adding the new one allowing the possibility of missing checks.
Or would this be solved by adding a second constraint under another
constraint name with the new constraint values and then dropping the
older one? If so, then ALTER TABLE ... RENAME CONSTRAINT would come in
handy.

--
Jeroen Ruigrok van der Werven <asmodai(at)wxs.nl> / asmodai
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