Message-ID: <00de01c23194$28c25360$c9bab23e@beeblebrox>
From: "Michael Paesold" <mpaesold@gmx.at>
To: <pgsql-sql@postgresql.org>
References: <023101c2318f$cee147b0$6602a8c0@salamander>
Subject: [NOVICE] SET CONSTRAINTS question...
Date: Mon, 22 Jul 2002 17:26:29 +0200
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Hi,

Right after installting postgres 7.2.1 (from release source) and reading
some chapters of Bruce Momjian's great book I started to play around with a
test database. Now I have a question concerning deferred constraint
checking.
I am new to transactional SQL, so I don't really know, if this should work:

-- create query
BEGIN;

CREATE TABLE friend (
 name VARCHAR(40) PRIMARY KEY,
 country CHAR(2) NOT NULL DEFAULT 'AT'
);

CREATE SEQUENCE conn_id_seq;
CREATE TABLE conn (
 id INTEGER NOT NULL DEFAULT nextval('conn_id_seq'),
 name VARCHAR(40),
 CONSTRAINT conn_friend_fkey FOREIGN KEY(name)
   REFERENCES friend(name)
   ON UPDATE CASCADE
   ON DELETE RESTRICT
   DEFERRABLE INITIALLY IMMEDIATE,
 CONSTRAINT conn_pkey PRIMARY KEY(id)
);
CREATE INDEX conn_name_idx ON conn (name);

INSERT INTO friend VALUES ('Michael Paesold', 'AT');
INSERT INTO conn (name) VALUES ('Michael Paesold');

COMMIT;

-- test
BEGIN;
SET CONSTRAINTS conn_friend_fkey DEFERRED;
DELETE FROM friend WHERE name='Michael Paesold';
INSERT INTO friend VALUES ('Michael Paesold', 'DE');
COMMIT;


I get an error just after the DELETE query. Perhaps I don't understand the
concept of deferred constraint checking. I know that the above query doesn't
make much sense, but I wanted to try these features.

Best Regards,
Michael Paesold