Funktionalitet som CHECK Constraints af andre produkter ville være passende i dette særlige tilfælde, men MySQL understøtter ikke denne funktion. Normalt bruges triggere ofte til at opnå det, du har brug for.
I det følgende eksempel, meget grundlæggende, valideres alle kolonner på triggeren, og når du forsøger at indsætte 50 poster, tager det et par millisekunder. Dette er blot et proof of concept, og det ville være praktisk for dig at udføre en test på et produktionslignende miljø.
/*Table structure for table `table_variables` */
DROP TABLE IF EXISTS `table_variables`;
CREATE TABLE `table_variables` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`variable0` TINYINT(4) DEFAULT NULL,
`variable1` TINYINT(4) DEFAULT NULL,
`variable2` TINYINT(4) DEFAULT NULL,
`variable3` TINYINT(4) DEFAULT NULL,
`variable4` TINYINT(4) DEFAULT NULL,
`variable5` TINYINT(4) DEFAULT NULL,
`variable6` TINYINT(4) DEFAULT NULL,
`variable7` TINYINT(4) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=INNODB;
/* Trigger structure for table `table_variables` */
DELIMITER $$
/*!50003 DROP TRIGGER*//*!50032 IF EXISTS */ /*!50003 `trg_check_bi` */$$
CREATE TRIGGER `trg_check_bi` BEFORE INSERT ON `table_variables`
FOR EACH ROW
BEGIN
DECLARE msg VARCHAR(255);
DECLARE _min, _max TINYINT DEFAULT -49;
SET _max := _max * (-1);
SET @max = _max;
IF (new.`variable0` NOT BETWEEN _min AND _max) THEN
SET msg := 'Error: variable0 out of range.';
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
END IF;
IF (new.`variable1` NOT BETWEEN _min AND _max) THEN
SET msg := 'Error: variable1 out of range.';
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
END IF;
IF (new.`variable2` NOT BETWEEN _min AND _max) THEN
SET msg := 'Error: variable2 out of range.';
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
END IF;
IF (new.`variable3` NOT BETWEEN _min AND _max) THEN
SET msg := 'Error: variable3 out of range.';
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
END IF;
IF (new.`variable4` NOT BETWEEN _min AND _max) THEN
SET msg := 'Error: variable4 out of range.';
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
END IF;
IF (new.`variable5` NOT BETWEEN _min AND _max) THEN
SET msg := 'Error: variable5 out of range.';
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
END IF;
IF (new.`variable6` NOT BETWEEN _min AND _max) THEN
SET msg := 'Error: variable6 out of range.';
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
END IF;
IF (new.`variable7` NOT BETWEEN _min AND _max) THEN
SET msg := 'Error: variable7 out of range.';
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
END IF;
END $$
DELIMITER ;
INSERT `table_variables` (
`variable0`,
`variable1`,
`variable2`,
`variable3`,
`variable4`,
`variable5`,
`variable6`,
`variable7`)
VALUES
(25, 46, 6, 42, 46, -42, -6, 47),
(11, -37, 26, -3, -44, 37, -28, -4),
(14, 33, -21, 40, 19, 23, 10, 29),
(-32, 1, -47, 10, 42, 36, 5, -34),
(-38, -40, -35, -6, 27, 7, 4, -49),
(-14, 29, 41, -29, -23, 22, 31, 41),
(-34, -49, 5, 27, -27, 30, -14, -11),
(36, -30, -14, -27, -44, 10, 33, -12),
(-10, 34, -42, 29, 29, 10, 11, -21),
(6, 45, -36, 29, 7, -3, 13, 25),
(37, -35, -40, -47, 32, -42, 38, -27),
(-4, 12, 24, 36, -39, 41, -22, 12),
(-19, 14, -18, 16, -15, 27, 31, 28),
(-3, -49, 11, -44, -8, 42, -8, -21),
(-31, -44, 21, -6, -42, -47, 38, -11),
(-21, -23, -1, 17, 36, -16, -40, -3),
(-43, 40, -16, 48, 43, 22, 29, 32),
(25, -21, -32, -47, 6, 28, -28, 23),
(-45, -48, 42, 11, -22, 4, 36, 24),
(-39, -21, -34, 39, -47, -10, 46, 16),
(-10, -48, 37, -15, -37, 8, 5, -47),
(-4, -25, 32, -8, 11, 31, -25, 26),
(-40, -30, 20, 44, 12, -22, -1, 16),
(32, -33, -14, -22, -19, 20, 13, -43),
(-10, 31, 39, -44, 8, 23, 44, 3),
(32, 3, -31, -15, -32, 34, 20, 47),
(30, -42, 44, 5, 41, 43, 44, 43),
(32, -16, -31, 43, -34, 45, -14, 37),
(-15, -38, 3, -17, -46, -31, 33, 12),
(13, -22, 0, 18, 42, 9, -31, -33),
(-23, 32, -16, -27, -38, 38, -40, 30),
(26, -9, 23, -4, -38, -31, 9, -11),
(-31, 25, -24, 48, -30, 48, -10, -47),
(41, 1, 31, 4, -21, 30, -33, -9),
(8, 16, 7, 39, 25, -38, -23, -47),
(-18, 1, 13, 13, -25, -14, -43, -25),
(-47, -11, 38, -23, 15, 0, 3, -31),
(-20, 44, 37, 4, -40, 33, 39, 47),
(-29, -40, 35, -46, 6, 21, 41, -4),
(4, -16, -42, -16, -1, -6, 23, -13),
(14, -40, 5, 0, 32, 16, 34, -24),
(24, 45, 7, -49, -22, -12, -43, -29),
(32, 1, -41, 38, -28, -11, -17, -5),
(-21, -39, 13, 37, -1, 32, 17, 40),
(-1, 25, -20, -26, -22, 18, 8, 37),
(13, 4, 32, 1, -41, 36, -38, 47),
(4, 26, -29, 25, -33, 5, -24, 15),
(-1, -1, 47, -4, -15, -11, 36, -29),
(-9, -7, 42, -14, -48, 47, 39, 3),
(-31, -20, 91, 17, -89, 4, -14, 22);