仅对一张表禁用触发器

Question

是否可以暂时禁用触发器，但仅针对一张表。

例如，我有一个表，带有插入、更新和删除触发器的 TableA。我也有一个具有相同触发器的表 B，但它们只影响表 A 中的某些列。

我现在有一个使用两个表的更新查询。我知道表 A 中的更新需要触发触发器，但表 B 中的更新绝对不需要触发触发器。所以我想禁用这些触发器，直到更新完成。

这可能吗？我正在使用 MySQL 5.1

[附录]

这是一个触发器表A本质上

BEGIN
    IF (OLD.status != 1 AND NEW.status = 2) THEN
        IF (OLD.geo_lat IS NOT NULL AND OLD.geo_long IS NOT NULL) THEN
            DELETE FROM geo WHERE datatype IN (3,4) AND foreignid = NEW.id;
        END IF;
    ELSEIF (OLD.Status = 1 AND NEW.Status != 2) THEN
        IF (NEW.geo_lat IS NOT NULL AND NEW.geo_long IS NOT NULL) THEN
            INSERT INTO geo (datatype, foreignid, long, lat, hostid, morton, status) VALUES  (IF(NEW.groupType=1,3,4), NEW.id, NEW.geo_long, NEW.geo_lat, NEW.hostid, 0, NEW.Status);
        END IF;
    ELSEIF (NEW.status != 3) THEN  
        IF (OLD.geo_lat IS NOT NULL AND OLD.geo_long IS NOT NULL AND (NEW.geo_lat IS NULL OR NEW.geo_long IS NULL)) THEN
            DELETE FROM geo WHERE datatype IN (3,4) AND foreignid = NEW.id;
        ElSEIF ((OLD.geo_lat IS NULL OR OLD.geo_long IS NULL) AND NEW.geo_lat IS NOT NULL AND NEW.geo_long IS NOT NULL) THEN
            INSERT INTO geo (datatype, foreignid, longitude, latitude, hostid, morton, status) VALUES  (IF(NEW.groupType=1,3,4), NEW.id, NEW.geo_long, NEW.geo_lat, NEW.hostid, 0, NEW.Status);
        ELSEIF (OLD.geo_lat!=NEW.geo_lat OR OLD.geo_long != NEW.geo_long OR OLD.status != NEW.status) THEN
            UPDATE geo SET lat = NEW.geo_lat, long = NEW.geo_long, status = NEW.status WHERE datatype IN (3,4) AND foreignid = NEW.id;
        END IF;
    END IF;
END

这里是表 B 上的触发器本质上

CREATE TRIGGER `usergroups_comments_insert` AFTER INSERT ON `usergroups_comment`
    FOR EACH ROW
    BEGIN
       CALL sp-set-comment_count(NEW.`gid`);
    END;

这是从表 B 中触发的存储过程

DELIMITER $$

CREATE PROCEDURE `sp_set-comment_count` (IN _id INT)
BEGIN
   -- AC   - All Count
   -- OLDAC- Old All Count
   DECLARE AC, OLDAC INT DEFAULT 0;

   SELECT COUNT(*) AS ac
     INTO AC
     FROM usergroups AS ug
LEFT JOIN usergroup_comments AS ugm ON ugm.`gid` = ug.`id`
LEFT JOIN mediagallery AS dm ON ugm.mid = dm.`id`
    WHERE dm.`status` NOT IN (200, 201, 202, 203, 204, 205)
      AND ug.`id` = _id;

   SELECT allCount
     INTO OLDAC
     FROM usergroups
    WHERE ug.`id` = _id;

IF (OLDAC <> AC) THEN 

   UPDATE usergroups
      SET allCount = AC,
    WHERE usergroups.`id` = _id;

END IF;

END $$

Answer 1

实际上，如果在每个触发器中放置一个 if then 块，就可以有效地关闭所有触发器。这是这样一个代码块

IF @TRIGGER_DISABLED = 0 THEN
    ...trigger body
END IF;

在mysql环境下，你可以

• 跑 SET @TRIGGER_DISABLED = 1;
• 做你的数据维护
• 跑 SET @TRIGGER_DISABLED = 0;

因此，表 A 的触发器应如下所示：

BEGIN 
    IF @TRIGGER_DISABLED = 0 THEN
    IF (OLD.status != 1 AND NEW.status = 2) THEN 
        IF (OLD.geo_lat IS NOT NULL AND OLD.geo_long IS NOT NULL) THEN 
            DELETE FROM geo WHERE datatype IN (3,4) AND foreignid = NEW.id; 
        END IF; 
    ELSEIF (OLD.Status = 1 AND NEW.Status != 2) THEN 
        IF (NEW.geo_lat IS NOT NULL AND NEW.geo_long IS NOT NULL) THEN 
            INSERT INTO geo (datatype, foreignid, long, lat, hostid, morton, status) VALUES  (IF(NEW.groupType=1,3,4), NEW.id, NEW.geo_long, NEW.geo_lat, NEW.hostid, 0, NEW.Status); 
        END IF; 
    ELSEIF (NEW.status != 3) THEN   
        IF (OLD.geo_lat IS NOT NULL AND OLD.geo_long IS NOT NULL AND (NEW.geo_lat IS NULL OR NEW.geo_long IS NULL)) THEN 
            DELETE FROM geo WHERE datatype IN (3,4) AND foreignid = NEW.id; 
        ElSEIF ((OLD.geo_lat IS NULL OR OLD.geo_long IS NULL) AND NEW.geo_lat IS NOT NULL AND NEW.geo_long IS NOT NULL) THEN 
            INSERT INTO geo (datatype, foreignid, longitude, latitude, hostid, morton, status) VALUES  (IF(NEW.groupType=1,3,4), NEW.id, NEW.geo_long, NEW.geo_lat, NEW.hostid, 0, NEW.Status); 
        ELSEIF (OLD.geo_lat!=NEW.geo_lat OR OLD.geo_long != NEW.geo_long OR OLD.status != NEW.status) THEN 
            UPDATE geo SET lat = NEW.geo_lat, long = NEW.geo_long, status = NEW.status WHERE datatype IN (3,4) AND foreignid = NEW.id; 
        END IF; 
    END IF; 
    END IF; 
END 

所以你的表 B 的触发器应该是这样的：

CREATE TRIGGER `usergroups_comments_insert` AFTER INSERT ON `usergroups_comment`     
    FOR EACH ROW     
    BEGIN     
        IF @TRIGGER_DISABLED = 0 THEN
            CALL sp-set-comment_count(NEW.`gid`);     
        END IF;
    END;     

如果您希望 A 表的触发器启动而不是 B 表的触发器，则只将代码块添加到 B 表的触发器中。