From: Gary Stainburn <gary.stainburn@ringways.co.uk>
To: pgsql-sql@postgresql.org
Subject: unique value - trigger?
Date: Thu, 17 Jul 2003 12:56:52 +0100
Message-ID: <200307171256.52098.gary.stainburn@ringways.co.uk> (raw)
Hi folks,
I'm back with my lnumbers table again.
nymr=# \d lnumbers
Table "lnumbers"
Column | Type | Modifiers
-----------+-----------------------+-----------
lnid | integer | not null
lnumber | character varying(10) | not null
lncurrent | boolean |
Primary key: lnumbers_pkey
Triggers: RI_ConstraintTrigger_7575462
While each loco can have a number of different numbers, only one can be
current at any one time.
I want to make it so that if I set lncurrent to true for one row, any existing
true rows are set to false.
I'm guessing that I need to create a trigger to be actioned after an insert or
update which would update set lncurrent=false where lnid not = <current lnid>
but I can't seem to sus it put.
--
Gary Stainburn
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To: pgsql-sql@postgresql.org
Cc: gary.stainburn@ringways.co.uk
Subject: Re: unique value - trigger?
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