CHECK Constraints के रूप में कार्यक्षमता इस विशेष मामले में अन्य उत्पाद उपयुक्त होंगे, लेकिन MySQL इस सुविधा का समर्थन नहीं करता है। आमतौर पर ट्रिगर्स का उपयोग अक्सर आपकी ज़रूरत को पूरा करने के लिए किया जाता है।
निम्नलिखित उदाहरण में, बहुत ही बुनियादी, सभी कॉलम ट्रिगर पर मान्य हैं और जब आप 50 रिकॉर्ड डालने का प्रयास करते हैं, तो इसमें कुछ मिलीसेकंड लगते हैं। यह केवल अवधारणा का प्रमाण है और आपके लिए उत्पादन जैसे वातावरण पर परीक्षण करना सुविधाजनक होगा।
/*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);
