Re: Automaticly delete related data

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On 2001 November 24 09:10 pm, Trond Arve Nordheim wrote:

> I'm developing a publishing system and are trying to create
> functions/triggers that automaticly wipes out related data to the data
> currently beeing deleted...

This can be achieve easily using Postgres' built in referential integrity stuff.

ie:
CREATE TABLE a (id SERIAL PRIMARY KEY, title TEXT NOT NULL);
CREATE TABLE b (id SERIAL PRIMARY KEY, data TEXT NOT NULL, key_a INTEGER REFERENCES a(id) ON DELETE CASCADE);

INSERT INTO a(title) VALUES ('test');
INSERT INTO b(data, key_a) VALUES ('test data', (SELECT id FROM a WHERE title='test'));
SELECT * FROM b; -- should list one row.
DELETE FROM a;
SELECT * FROM b; -- should list no rows.

Take a look at the doc's for CREATE TABLE in the SQL reference.

- -- 
Andrew G. Hammond     mailto:drew@xyzzy.dhs.org   http://xyzzy.dhs.org/~drew/
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"To blow recursion you must first blow recur" -- me
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