oops, just realised that doesn't work when you get further than 10.
> -----Original Message----- > From: Richard B. Boulton [mailto:[EMAIL PROTECTED] > Sent: 24 December 2005 10:37 > To: sqlite-users@sqlite.org > Subject: RE: [sqlite] ring buffer table > > > If you used an INTEGER PRIMARY KEY AUTOINCREMENT could you > use a simple trigger and a modulus of the newly inserted rowid? > > e.g. for a dimension of 10: > > CREATE TABLE ring_buffer (key INTEGER PRIMARY KEY > AUTOINCREMENT, stuff TEXT); > CREATE TRIGGER delete_tail AFTER INSERT ON ring_buffer > BEGIN > DELETE FROM ring_buffer WHERE key=NEW.key%10 AND key!=NEW.key; > END; > INSERT INTO ring_buffer (stuff) VALUES('Stuff 1'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 2'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 3'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 4'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 5'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 6'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 7'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 8'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 9'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 10'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 11'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 12'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 13'); > INSERT INTO ring_buffer (stuff) VALUES('Stuff 14'); > SELECT * FROM ring_buffer; > > 5|Stuff 5 > 6|Stuff 6 > 7|Stuff 7 > 8|Stuff 8 > 9|Stuff 9 > 10|Stuff 10 > 11|Stuff 11 > 12|Stuff 12 > 13|Stuff 13 > 14|Stuff 14 > > > Hi, > > I would like to implement a log table with a finite > > dimension, for exemple a > > table with 500 records, and when the last record is set in > > the table I would > > like to come back at the first tuplet and write over the > > previous value > > recorded. I think it's the way SQLite journal is implmented. > > Is there any way to declare this table with these properties > > included, so I > > don't have to add code to do this function? > > Thanks > > > > Julien > > > > ---------------------------- > > Julien LEFORT > > Com2gether > > 16, Allée de la verte vallée > > 14000 CAEN > > tel : +33 2 31 15 61 42 > > fax : +33 2 31 53 76 14 > > >
