Jak uložit informace o výjimce / selhání MySQL Trigger do tabulky nebo do proměnných

Našel jsem hack přes DECLARE CONTINUE HANDLER a GET DIAGNOSTICS CONDITION , tak jsem si myslel, že to musím sdílet zde.

Zde je můj kompletní závěrečný skript, který udržuje zálohu (synchronizaci) pro obě databáze users co to znamená, že jakákoli aktualizace na test_db1 (který můžeme nazvat jako productionDB) se objeví na test_db2 (kterému můžeme říkat stagingDB):

/*
Create two databases:
    1. `test_db1`
    2. `test_db2`
and execute below create *Table script* on both databases.
after that execute *Triggers Script* on `test_db1` only..
*/

/*
    TABLE STRUCTURE FOR `users`
*/

DROP TABLE IF EXISTS `users`;
CREATE TABLE IF NOT EXISTS `users` (
  `id` int(11) AUTO_INCREMENT NOT NULL,
  `name` varchar(30) NOT NULL,
  `age` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

/*
    TABLE STRUCTURE FOR `errors`
*/

DROP TABLE IF EXISTS `errors`;
CREATE TABLE IF NOT EXISTS `errors` (
  `id` int(11) AUTO_INCREMENT NOT NULL,
  `code` varchar(30) NOT NULL,
  `message` TEXT NOT NULL,
  `query_type` varchar(50) NOT NULL,
  `record_id` int(11) NOT NULL,
  `on_db` varchar(50) NOT NULL,
  `on_table` varchar(50) NOT NULL,
  `emailed` TINYINT DEFAULT 0,
  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

/*
    TRIGGERS SCRIPTS FOR INSERT, UPDATE AND DELETE OPERATIONS
*/

DELIMITER //

-- TRIGGER FOR INSERT
DROP TRIGGER IF EXISTS `test_db1_users_ai`;
CREATE TRIGGER `test_db1_users_ai` AFTER INSERT ON `users` FOR EACH ROW 
BEGIN
    -- Declare variables to hold diagnostics area information
    DECLARE errorCode CHAR(5) DEFAULT '00000';
    DECLARE errorMessage TEXT DEFAULT '';

    -- Declare exception handler for failed insert
    DECLARE CONTINUE HANDLER FOR SQLEXCEPTION 
    BEGIN
      GET DIAGNOSTICS CONDITION 1
        errorCode = RETURNED_SQLSTATE, errorMessage = MESSAGE_TEXT;
    END;

    -- Perform the insert
    INSERT INTO `test_db2`.`users` (id, name, age) VALUES (NEW.id, NEW.name, NEW.age);

    -- Check whether the insert was successful
    IF errorCode != '00000' THEN
        INSERT INTO `errors` (code, message, query_type, record_id, on_db, on_table) VALUES (errorCode, errorMessage, 'insert', NEW.id, 'test_db2', 'users');
    END IF;
END; //

-- TRIGGER FOR UPDATE
DROP TRIGGER IF EXISTS `test_db1_users_au`;
CREATE TRIGGER `test_db1_users_au` AFTER UPDATE ON `users` FOR EACH ROW 
BEGIN
    -- Declare variables to hold diagnostics area information
    DECLARE errorCode CHAR(5) DEFAULT '00000';
    DECLARE errorMessage TEXT DEFAULT '';

    -- Declare exception handler for failed insert
    DECLARE CONTINUE HANDLER FOR SQLEXCEPTION 
    BEGIN
      GET DIAGNOSTICS CONDITION 1
        errorCode = RETURNED_SQLSTATE, errorMessage = MESSAGE_TEXT;
    END;

    -- Perform the update
    UPDATE `test_db2`.`users`
        SET name = NEW.name,
            age = NEW.age
        WHERE id = NEW.id;

    -- Check whether the update was successful
    IF errorCode != '00000' THEN
        INSERT INTO `errors` (code, message, query_type, record_id, on_db, on_table) VALUES (errorCode, errorMessage, 'update', NEW.id, 'test_db2', 'users');
    END IF;
END; //

-- TRIGGER FOR DELETE
DROP TRIGGER IF EXISTS `test_db1_users_ad`;
CREATE TRIGGER `test_db1_users_ad` AFTER DELETE ON `users` FOR EACH ROW 
BEGIN
    -- Declare variables to hold diagnostics area information
    DECLARE errorCode CHAR(5) DEFAULT '00000';
    DECLARE errorMessage TEXT DEFAULT '';

    -- Declare exception handler for failed insert
    DECLARE CONTINUE HANDLER FOR SQLEXCEPTION 
    BEGIN
      GET DIAGNOSTICS CONDITION 1
        errorCode = RETURNED_SQLSTATE, errorMessage = MESSAGE_TEXT;
    END;

    -- Perform the delete
    DELETE FROM `test_db2`.`users`
        WHERE id = OLD.id;

    -- Check whether the insert was successful
    IF errorCode != '00000' THEN
        INSERT INTO `errors` (code, message, query_type, record_id, on_db, on_table) VALUES (errorCode, errorMessage, 'delete', OLD.id, 'test_db2', 'users');
    END IF;
END; //

-- DELIMITER;

Doufám, že to pomůže ostatním, až sem přijdou.

Na zdraví,