使用复合主键更新后的MySQL触发器失败

我想将更改保存到我的远程表中，以便与Android应用程序同步.

包含数据的表定义为:

CREATE TABLE `lh_psalm_join` (
  `groupFK` int(11) NOT NULL,
  `readingFK` int(11) NOT NULL,
  `theOrder` int(11) NOT NULL,
  `themeFK` int(11) DEFAULT NULL,
  `epigraphFK` int(11) DEFAULT NULL,
  `thePart` int(11) DEFAULT NULL,
  PRIMARY KEY (`groupFK`,`readingFK`),
  KEY `readingFK` (`readingFK`),
  KEY `epigraphFK` (`epigraphFK`),
  KEY `themeFK` (`themeFK`),
  CONSTRAINT `lh_psalm_join_ibfk_1` FOREIGN KEY (`groupFK`) REFERENCES `lh_psalmody_join` (`groupID`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `lh_psalm_join_ibfk_2` FOREIGN KEY (`readingFK`) REFERENCES `lh_psalm` (`psalmID`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `lh_psalm_join_ibfk_3` FOREIGN KEY (`epigraphFK`) REFERENCES `lh_epigraph` (`epigraphID`) ON DELETE SET NULL ON UPDATE CASCADE,
  CONSTRAINT `lh_psalm_join_ibfk_4` FOREIGN KEY (`themeFK`) REFERENCES `lh_theme` (`themeID`) ON DELETE SET NULL ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_spanish_ci

这是一个关于sincronization的表格:

CREATE TABLE `sync_lh_psalm_join` (
  `groupFK` int(11) NOT NULL,
  `readingFK` int(11) NOT NULL,
  `crud` char(1) DEFAULT NULL,
  `lastUpdate` timestamp NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
  PRIMARY KEY (`groupFK`,`readingFK`),
  CONSTRAINT `sync_lh_psalm_join_ibfk_1` FOREIGN KEY (`groupFK`, `readingFK`) REFERENCES `lh_psalm_join` (`groupFK`, `readingFK`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_spanish_ci

当在lh_psalm_join中插入或更新一行时，我希望在sync_lh_psalm_join中保存一个引用，以便通过判断lastUpdate字段来执行同步.

为此，我定义了这个触发器:

DROP TRIGGER IF EXISTS `lh_psalm_join_after_update`;
DELIMITER $$
CREATE TRIGGER `lh_psalm_join_after_update` AFTER UPDATE ON `lh_psalm_join` FOR EACH ROW
BEGIN
  DECLARE countRows INT(11) DEFAULT 0;
  SELECT 
    COUNT(*) 
  FROM `sync_lh_psalm_join` 
  WHERE 
    `groupFK`=NEW.`groupFK` AND 
    `readingFK`=NEW.`readingFK` 
  INTO countRows;
  IF countRows>0 THEN
    UPDATE `sync_lh_psalm_join` SET 
      `groupFK`=NEW.`groupFK`,
      `readingFK`=NEW.`readingFK`,
      `crud`='u', 
      `lastUpdate`=CURRENT_TIMESTAMP 
    WHERE 
      `groupFK`=OLD.`groupFK` AND 
      `readingFK`=OLD.`readingFK`;
  ELSE
    INSERT INTO `sync_lh_psalm_join` 
      (`groupFK`,`readingFK`,`crud`) 
    VALUES
      (NEW.`groupFK`,NEW.`readingFK`,'u');
  END IF;
  CALL spUpdateSyncStatus('lh_psalm_join');
END$$
DELIMITER ;

由于可能已经存在具有主键的记录，我的 idea 是在更新时将该记录更改为主键的新值，并将lastUpdate列的值更改为CURRENT_TIMESTAMP.

但它不起作用，如果我try 主键已经存在于sync_lh_psalm_join中的某行的lh_psalm_join中的UPDATE，它会给我这个错误:

无法删除或更新父行:外键约束失败 (c39b075_deiverbu.sync_lh_psalm_join，约束 sync_lh_psalm_join_ibfk_1 FOREIGN KEY(groupFK，readingFK) 参考文献lh_psalm_join(groupFK，readingFK))

如果我将WHERE更改为:

    WHERE 
      `groupFK`=NEW.`groupFK` AND 
      `readingFK`=NEW.`readingFK`;

我的方法有什么问题吗？