Mailbox-Line: From mallah@trade-india.com  Sun Jul  7 09:41:48 2002
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From: "Rajesh Kumar Mallah." <mallah@trade-india.com>
Organization: Infocom Network Limited.
To: "Christopher Kings-Lynne" <chriskl@familyhealth.com.au>,
	<pgsql-sql@postgresql.org>
Subject: Re: Is Dropping a column "CHECK" constraint possible?
Date: Sun, 7 Jul 2002 19:15:10 +0530
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	<00e101c224a6$81ee3bc0$0200a8c0@SOL>
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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=3D>  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=3D# \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)
> >