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MySQL-Trigger zum Prüfen von Werten vor mehrmaligem Einfügen

Funktionalität wie die CHECK Constraints anderer Produkte wäre in diesem speziellen Fall angemessen, aber MySQL unterstützt diese Funktion nicht. Normalerweise werden Trigger oft verwendet, um das zu erreichen, was Sie brauchen.

Im folgenden sehr einfachen Beispiel werden alle Spalten auf dem Trigger validiert, und wenn Sie versuchen, 50 Datensätze einzufügen, dauert es einige Millisekunden. Dies ist nur ein Machbarkeitsnachweis und es wäre praktisch für Sie, einen Test in einer produktionsähnlichen Umgebung durchzuführen.

/*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);