RULE: ON DELETE doesn't stack deletes

From: Malcolm Hutty <msah-postgres(at)hutty(dot)com>
To: pgsql-bugs(at)postgresql(dot)org
Subject: RULE: ON DELETE doesn't stack deletes
Date: 2002-11-20 15:49:09
Message-ID: 3DDBAEF5.1030401@hutty.com
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According to the manual you can stack multiple queries in a RULE:

CREATE RULE name AS ON event
TO object [ WHERE condition ]
DO [ INSTEAD ] action

where action can be:

NOTHING
|
query
|
( query ; query ... )
|
[ query ; query ... ]

This seems to work provided 'query' is not "DELETE"; if it is, only
the first one is executed.

My installation is Postgres 7.2.2, using the binary package shipped in
Redhat 8.0

[malcolm(at)localhost STRUCT]$ uname -sr
Linux 2.4.18-18.8.0

Here is a test case:

CREATE TABLE A
(a_data int);

CREATE TABLE B
(b_data int);

CREATE VIEW V_AB AS
SELECT a_data,b_data FROM A,B;

CREATE RULE R_DEL_AB AS
ON DELETE TO V_AB
DO INSTEAD
(
DELETE FROM A WHERE a_data=OLD.a_data;
DELETE FROM B WHERE b_data=OLD.b_data;
);

INSERT INTO A values (1);
INSERT INTO B values (1);

test=# select * from V_AB;
a_data | b_data
--------+--------
1 | 1
(1 row)

test=#delete from v_ab;
DELETE 0

test=# select * from a;
a_data
--------
(0 rows)

test=# select * from b;
b_data
--------
1
(1 row)

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