用戶表
CREATE TABLE `USERS` ( `ID` char(255) COLLATE utf8_unicode_ci NOT NULL, `NAME` char(255) COLLATE utf8_unicode_ci NOT NULL, `EMAIL` char(255) COLLATE utf8_unicode_ci DEFAULT NULL, `CREATED_IN` datetime NOT NULL, `SIGNED_IN` datetime NOT NULL, PRIMARY KEY (`ID`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci
觸發器
CREATE TRIGGER `ABC` BEFORE INSERT ON `USERS` FOR EACH ROW IF NEW.ID = "" OR NEW.NAME = "" OR NEW.CREATED_IN = "" OR NEW.CREATED_IN = "0000-00-00 00:00:00" OR NEW.SIGNED_IN = "" OR NEW.SIGNED_IN = "0000-00-00 00:00:00" THEN SIGNAL SQLSTATE "45000"; END IF
ID欄位
#如何使其不接受空值？ ("", " ", " ", " ", 等等...) -> 應該回傳錯誤#如果已經有一個值，如何刪除其中的所有空格？ ("bf9 d 34 c9 08" = "bf9d34c908")名稱列
如何使其不接受空值？ ("", " ", " ", " ", 等等...) -> 應該回傳錯誤#電子郵件列
如何使其不接受空值？ ("", " ", " ", " ", 等等...) -> 應該回傳錯誤#如果已經有一個值，如何刪除其中的所有空格？ ("nkr owks lpehqp jmgdb @ gm ail.com" = "[電子郵件受保護]")#CREATED_IN 和 SIGNED_IN 欄位
MySQL版本是5.7
在 USERS 表上處理這些要求的最佳方法是什麼？ ###
觸發器可以如下所示：
CREATE TRIGGER process_input BEFORE INSERT ON USERS FOR EACH ROW BEGIN SET NEW.id = REPLACE(NEW.id, ' ', ''); IF NEW.id = '' THEN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = '`id` cannot be empty.'; END IF; SET NEW.name = TRIM(NEW.name); IF NEW.name = '' THEN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = '`name` cannot be empty.'; END IF; SET NEW.email = REPLACE(NEW.email, ' ', ''); IF NEW.email = '' THEN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = '`email` cannot be empty.'; END IF; IF STR_TO_DATE(created_in, '%Y-%m-%d %H:%i:%s') IS NULL THEN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'Incorrect `created_in` datetime value.'; END IF; IF STR_TO_DATE(signed_in, '%Y-%m-%d %H:%i:%s') IS NULL THEN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'Incorrect `signed_in` datetime value.'; END IF; END注意 - 此觸發器允許任何值為 NULL（但只有電子郵件可以為 NULL，所有其他欄位都定義為 NOT NULL）。
你可以重新排列這些區塊，並將機率最大的條件放在第一位。執行 SIGNAL 後觸發器不會執行下列程式碼。