I found an excellent description of how to implement a fifo que in PostgreSQL at Greg Mullane's blog: http://people.planetpostgresql.org/greg/index.php?/archives/89-Implementing-a-queue-in-SQL-Postgres-version.html I have used the 'rule' approach to implement a queue that generates a quick-list of last selected places. The only modification I need is that if an item already exists in the list, a new reference should be written to the top, and the old reference should be deleted. But it seems like I'm in over my head here: -- short FIFO list of recently selected places CREATE TABLE recent_places ( id SERIAL PRIMARY KEY, place_fk INTEGER REFERENCES places ON DELETE CASCADE ); CREATE RULE placelimit AS ON INSERT TO recent_places DO ALSO DELETE FROM recent_places WHERE -- this clause doesn't work -- (place_fk = NEW.place_fk AND id <> NEW.id) OR id NOT IN (SELECT id FROM recent_places ORDER BY id DESC LIMIT 10); When I try to use the commented clause above, no records are written to the table at all! Why? -- Leif Biberg Kristensen | Registered Linux User #338009 http://solumslekt.org/ | Cruising with Gentoo/KDE My Jazz Jukebox: http://www.last.fm/user/leifbk/ ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly
