Subject: time of constraint checking
From: Markus Bertheau <twanger@bluetwanger.de>
To: pgsql-sql@postgresql.org
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Message-Id: <1098287892.2649.15.camel@dicaprio.akademie1.de>
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Date: Wed, 20 Oct 2004 17:58:12 +0200
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Hi,

http://www.postgresql.org/docs/current/static/sql-createtable.html says,
down at the explanation of DEFERRABLE, that constraints are checked
after every command. Why does the following not work then:

CREATE TABLE foo (
    pos INT UNIQUE
);
 
INSERT INTO foo (pos) VALUES (1);
INSERT INTO foo (pos) VALUES (2);
 
UPDATE foo SET pos = CASE WHEN pos = 2 THEN 1 ELSE 2 END;
ERROR:  duplicate key violates unique constraint "foo_pos_key"

Also, are deferrable constraints other that FK constraints in the works?
I also noticed, that the docs don't state whether INITIALLY IMMEDIATE or
INITIALLY DEFERRED is the default.

Thanks.

-- 
Markus Bertheau <twanger@bluetwanger.de>