--source include/have_innodb.inc

CREATE TABLE tx_shoutbox (
  uid int(11) unsigned NOT NULL auto_increment,
  cr_date int(11) unsigned NOT NULL default '0',
  `name` varchar(20) collate utf8_unicode_ci NOT NULL,
  nachricht varchar(256) collate utf8_unicode_ci NOT NULL,
  PRIMARY KEY  (uid)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

INSERT INTO `tx_shoutbox` (`uid`, `cr_date`, `name`, `nachricht`) VALUES
(25, 1241575767, 'David', '11'),
(26, 1241575768, 'David', '12'),
(27, 1241575769, 'David', '113'),
(28, 1241575841, 'David', 'qweqw'),
(29, 1241576071, 'David', 'juju'),
(30, 1241576336, 'David', 'naaa????'),
(31, 1241576387, 'David', 'oh!'),
(32, 1241576775, 'David', 'You can say, that this is practically out of tûne'),
(33, 1241577036, 'David', 'Go!'),
(34, 1241577290, 'ja', 'nein'),
(35, 1241577298, 'ja', 'nein'),
(36, 1241577351, 'nein', 'ja'),
(37, 1241577555, 'nein', 'kiki'),
(38, 1241577645, 'nein', ':hapydance:'),
(39, 1241577660, 'nein', ':tee-hee:'),
(40, 1241597392, 'juhu', '22'),
(41, 1241597395, 'juhu', '45'),
(42, 1241597396, 'juhu', '435'),
(43, 1241597396, 'juhu', '2534'),
(44, 1241597396, 'juhu', '34'),
(45, 1241597397, 'juhu', '34'),
(46, 1241597397, 'juhu', '34'),
(47, 1241597397, 'juhu', '534'),
(48, 1241597397, 'juhu', '53'),
(49, 1241597397, 'juhu', '453'),
(50, 1241597398, 'juhu', '45'),
(51, 1241597398, 'juhu', '345'),
(52, 1241597398, 'juhu', '2345'),
(53, 1241597398, 'juhu', '2354'),
(54, 1241597399, 'juhu', '34'),
(55, 1241597399, 'juhu', '5234');


delimiter //;
CREATE TRIGGER tr_shoutbox AFTER INSERT ON tx_shoutbox
FOR EACH ROW
BEGIN
DECLARE r integer;
SET r = (SELECT MAX(uid)-15 FROM tx_shoutbox);
DELETE FROM tx_shoutbox WHERE uid<r;
END;//
delimiter ;//

select * from tx_shoutbox;

insert into tx_shoutbox (name) values('z');

select * from tx_shoutbox;