MariaDB 不允许正确使用 SIGNAL

Question

可能相关：MySQL trigger definition - 1064 error

嗨，

我正在尝试在 MariaDB 10.4.10-GA 中的用户表上添加触发器。目的是，用户可以设置第二个邮件地址，但该邮件地址不能与第一个邮件地址相同。给定触发器的代码：

CREATE TRIGGER MyValidator
  BEFORE INSERT
  ON User
  FOR EACH ROW
BEGIN
  IF NEW.U_Mail LIKE '%_@%_.%' THEN
    IF NEW.U_AlternateMail LIKE NEW.U_Mail THEN
      SIGNAL SQLSTATE VALUE '45001'
      SET MESSAGE_TEXT = 'User - Mail already set';
    ELSEIF NEW.U_AlternateMail NOT LIKE '%_@%_.%' THEN
      SIGNAL SQLSTATE VALUE '45002'
      SET MESSAGE_TEXT = 'User - Not a Mail';
    END IF;
  ELSE
    SIGNAL SQLSTATE VALUE '45000'
    SET MESSAGE_TEXT = 'User - Bad Mail in database';
  END IF;
END;

MariaDB 告诉我：

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 9

这将是SET 语句。甚至只是在BEGIN 之后添加SET testvar="text";。产生相同的错误，只是将新行作为错误行。 我已经在这个问题上坐了几个小时，在互联网上找不到任何有用的东西。 根据文档，这个 SQL 代码应该是正确的：https://mariadb.com/kb/en/library/signal/ 有趣的是，上述链接中的此示例代码也无法使用相同的错误：

CREATE PROCEDURE test_error(x INT)
BEGIN
   DECLARE errno SMALLINT UNSIGNED DEFAULT 31001;
   SET @errmsg = 'Hello, world!';
   IF x = 1 THEN
      SIGNAL SQLSTATE '45000' SET
      MYSQL_ERRNO = errno,
      MESSAGE_TEXT = @errmsg;
   ELSE
      SIGNAL SQLSTATE '45000' SET
      MYSQL_ERRNO = errno,
      MESSAGE_TEXT = _utf8'Hello, world!';
   END IF;
END;

任何想法，可能是什么问题？

问候

Answer 1

确保在添加触发器、函数或存储过程定义时使用delimiter。

不确定您使用的是命令行还是其他工具，例如 workbench 或 phpmyadmin，但无论哪种方式都一样。

我用分隔符将您的触发语句粘贴到我的命令行中：

delimiter //
CREATE TRIGGER MyValidator
  BEFORE INSERT
  ON User
  FOR EACH ROW
BEGIN
  IF NEW.U_Mail LIKE '%_@%_.%' THEN
    IF NEW.U_AlternateMail LIKE NEW.U_Mail THEN
      SIGNAL SQLSTATE VALUE '45001'
      SET MESSAGE_TEXT = 'User - Mail already set';
    ELSEIF NEW.U_AlternateMail NOT LIKE '%_@%_.%' THEN
      SIGNAL SQLSTATE VALUE '45002'
      SET MESSAGE_TEXT = 'User - Not a Mail';
    END IF;
  ELSE
    SIGNAL SQLSTATE VALUE '45000'
    SET MESSAGE_TEXT = 'User - Bad Mail in database';
  END IF;
END;
//

运行时（第一次切换到数据库后），输出为：

MariaDB [(none)]> use test
Database changed
MariaDB [test]> delimiter //
MariaDB [test]> CREATE TRIGGER MyValidator
    ->   BEFORE INSERT
    ->   ON User
    ->   FOR EACH ROW
    -> BEGIN
    ->   IF NEW.U_Mail LIKE '%_@%_.%' THEN
    ->     IF NEW.U_AlternateMail LIKE NEW.U_Mail THEN
    ->       SIGNAL SQLSTATE VALUE '45001'
    ->       SET MESSAGE_TEXT = 'User - Mail already set';
    ->     ELSEIF NEW.U_AlternateMail NOT LIKE '%_@%_.%' THEN
    ->       SIGNAL SQLSTATE VALUE '45002'
    ->       SET MESSAGE_TEXT = 'User - Not a Mail';
    ->     END IF;
    ->   ELSE
    ->     SIGNAL SQLSTATE VALUE '45000'
    ->     SET MESSAGE_TEXT = 'User - Bad Mail in database';
    ->   END IF;
    -> END;
    -> //
Query OK, 0 rows affected (0.11 sec)

...然后检查information_schema：

MariaDB [test]> select trigger_schema, event_object_table, action_timing, action_statement from information_schema.triggers where trigger_name = 'MyValidator' \G
*************************** 1. row ***************************
    trigger_schema: test
event_object_table: user
     action_timing: BEFORE
  action_statement: BEGIN
  IF NEW.U_Mail LIKE '%_@%_.%' THEN
    IF NEW.U_AlternateMail LIKE NEW.U_Mail THEN
      SIGNAL SQLSTATE VALUE '45001'
      SET MESSAGE_TEXT = 'User - Mail already set';
    ELSEIF NEW.U_AlternateMail NOT LIKE '%_@%_.%' THEN
      SIGNAL SQLSTATE VALUE '45002'
      SET MESSAGE_TEXT = 'User - Not a Mail';
    END IF;
  ELSE
    SIGNAL SQLSTATE VALUE '45000'
    SET MESSAGE_TEXT = 'User - Bad Mail in database';
  END IF;
END
1 row in set (0.01 sec)