Pemicu MySQL untuk memeriksa nilai sebelum memasukkan beberapa kali

Fungsionalitas sebagai CHECK Constraints produk lain akan sesuai dalam kasus khusus ini, tetapi MySQL tidak mendukung fitur ini. Biasanya pemicu sering digunakan untuk mencapai apa yang Anda butuhkan.

Dalam contoh berikut, sangat mendasar, semua kolom divalidasi pada pemicu dan ketika Anda mencoba memasukkan 50 catatan, dibutuhkan beberapa milidetik. Ini hanyalah bukti konsep dan akan lebih mudah bagi Anda untuk melakukan pengujian pada lingkungan seperti produksi.

/*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);