Thread: Is Dropping a column "CHECK" constraint possible?
Hi Folks ,
can anyone please help?
i have a to drop a check contstraint from a column. eg
tradein_clients=# \d t_a Table "t_a" Column | Type | Modifiers
------------+---------+-----------company_id | integer |exp | text |imp | text |
Check constraints: "$1" (length(imp) > 1) "aaaaaq" (length(imp) > 1)
Can i remove to contraints thru ALTER TABLE or similar commands.
I have read the docs for ALTER TABLE but the command described is
not working for me.
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ALTER TABLE [ ONLY ] table DROP CONSTRAINT constraint { RESTRICT | CASCADE }
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Regards
Mallah.
--
Rajesh Kumar Mallah,
Project Manager (Development)
Infocom Network Limited, New Delhi
phone: +91(11)6152172 (221) (L) ,9811255597 (M)
Visit http://www.trade-india.com ,
India's Leading B2B eMarketplace.
> can anyone please help? > i have a to drop a check contstraint from a column. eg > > tradein_clients=# \d t_a > Table "t_a" > Column | Type | Modifiers > ------------+---------+----------- > company_id | integer | > exp | text | > imp | text | > Check constraints: "$1" (length(imp) > 1) > "aaaaaq" (length(imp) > 1) > > Can i remove to contraints thru ALTER TABLE or similar commands. > I have read the docs for ALTER TABLE but the command described is > not working for me. This should work, so long as you're using postgres 7.2+ ALTER TABLE "t_a" DROP CONSTRAINT "aaaaaq" RESTRICT; Chris
Yup it did!. Thanks a ton, it was there in the ALTER TABLE documentation i overlooked :-( regds mallah. On Saturday 06 July 2002 10:05, Christopher Kings-Lynne wrote: > > can anyone please help? > > i have a to drop a check contstraint from a column. eg > > > > tradein_clients=# \d t_a > > Table "t_a" > > Column | Type | Modifiers > > ------------+---------+----------- > > company_id | integer | > > exp | text | > > imp | text | > > Check constraints: "$1" (length(imp) > 1) > > "aaaaaq" (length(imp) > 1) > > > > Can i remove to contraints thru ALTER TABLE or similar commands. > > I have read the docs for ALTER TABLE but the command described is > > not working for me. > > This should work, so long as you're using postgres 7.2+ > > ALTER TABLE "t_a" DROP CONSTRAINT "aaaaaq" RESTRICT; > > Chris -- Rajesh Kumar Mallah, Project Manager (Development) Infocom Network Limited, New Delhi phone: +91(11)6152172 (221) (L) ,9811255597 (M) Visit http://www.trade-india.com , India's Leading B2B eMarketplace.
Hi , i want to enforce that a coulumn 'imp' shud either contain valid data or no data at all. by valid data i mean data having at least one non whitespace character. will this constraint be approprote for accomplishing it? tradein_client=> ALTER TABLE t_a ADD CHECK ( length( btrim(imp) ) > 1 or imp is NULL ); regards mallah. On Saturday 06 July 2002 10:05, Christopher Kings-Lynne wrote: > > can anyone please help? > > i have a to drop a check contstraint from a column. eg > > > > tradein_clients=# \d t_a > > Table "t_a" > > Column | Type | Modifiers > > ------------+---------+----------- > > company_id | integer | > > exp | text | > > imp | text | > > Check constraints: "$1" (length(imp) > 1) > > "aaaaaq" (length(imp) > 1) > >