如何防止 MySQL 中出现空格、空值和无效日期？

Question

用户table

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

触发器

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列

如何让它不接受空值？ ("", " ", " ", " ", etc...) -> Should return an error
如果已经有一个值，我怎样才能从中删除所有空格？ ("bf9 d 34 c9 08" = "bf9d34c908")

NAME 列

如何让它不接受空值？ ("", " ", " ", " ", etc...) -> Should return an error

EMAIL 列

如何让它不接受空值？ ("", " ", " ", " ", etc...) -> Should return an error
如果已经有一个值，我怎样才能从中删除所有空格？ ("nkr owks lpehqp jmgdb @ gm ail. com" = "nkrowkslpehqpjmgdb@gmail.com")

CREATED_IN 和 SIGNED_IN 列

如何让它不接受无效值？当插入无效值（如字母、数字或无效格式）时，应该 return 出错而不是输入 0000-00-00 00:00:00.

MySQL version is 5.7

处理用户 table 的这些要求的最佳方法是什么？

Answer 1

触发器可能如下所示：

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 - 此触发器允许任何值中的 NULL（但只有电子邮件可以为 NULL，所有其他列都定义为 NOT NULL）。

你可以对块进行排序，把概率最大的条件放在最前面。 SIGNAL执行后触发器不执行下面的代码。

如何防止 MySQL 中出现空格、空值和无效日期？

How can I prevent white spaces, empty values, and invalid dates in MySQL?

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