如果我使用"更新后"而不是"插入后",MYSQL Trigger会起作用吗？

Question

在表a上的操作之后,我写了一个触发器来在表b中插入一行.出于某种原因,如果我在插入后添加此触发器然后插入一行,则无效.但是,如果我将触发器添加为"更新后"并更新行,它确实有效.

这是触发器代码.当我用'AFTER INSERT'替换'AFTER UPDATE'并进行插入时,插入新行时没有任何反应.创建触发器时我没有错误,我也没有尝试更新触发器所在的同一个表.任何帮助表示赞赏!谢谢,Jen

drop trigger if exists insertUndecided;  
DELIMITER //  
CREATE TRIGGER insertUndecided  
     AFTER UPDATE ON jiraissue
     FOR EACH ROW
     BEGIN
        insert into nodeassociation (SOURCE_NODE_ID, SOURCE_NODE_ENTITY, SINK_NODE_ID, SINK_NODE_ENTITY, ASSOCIATION_TYPE, SEQUENCE)
   select
      NEW.id as SOURCE_NODE_ID,
      'Issue' as SOURCE_NODE_ENTITY,
      (select pv.id from projectversion pv
         where pv.vname='undecided'
         and pv.project=NEW.project ) as SINK_NODE_ID,
      'Version' as SINK_NODE_ENTITY,
      'IssueFixVersion' as ASSOCIATION_TYPE,
      NULL as SEQUENCE

   from dual  where exists
      (select pkey from jiraissue
         where id=NEW.id and id not in
            (select distinct source_node_id from nodeassociation
               where source_node_entity='Issue' and SINK_NODE_ENTITY='Version'
               and ASSOCIATION_TYPE='IssueFixVersion') );

 END;//

DELIMITER ;

Answer 1

在带有 InnoDB 表的 MySQL 5.5.20 上，我在简化的测试中重现了您的情况。两者都使用触发器表中引用新行的结果进行插入，并使用新值直接插入效果很好

CREATE TABLE test1(a1 INT NOT NULL auto_increment, b1 INT, PRIMARY KEY (a1) );
CREATE TABLE test2(a1 INT, b1 INT);
CREATE TABLE test3(a1 INT, b1 INT);

DELIMITER ;;

CREATE TRIGGER testAI AFTER INSERT ON test1
  FOR EACH ROW BEGIN
    INSERT INTO test2 SET a1 = NEW.a1, b1 = NEW.b1;
    INSERT INTO test3 ( a1, b1 ) SELECT a1, b1 FROM test1 WHERE a1 = NEW.a1;
  END;
;;

DELIMITER ;

扣动扳机

INSERT INTO test1 (b1) VALUES (1),(2),(3);

直接从新值插入

mysql> SELECT * FROM test2;
+------+------+
| a1   | b1   |
+------+------+
|    1 |    1 |
|    2 |    2 |
|    3 |    3 |
+------+------+
3 rows in set (0.00 sec)

从 SELECT 结果插入

mysql> SELECT * FROM test3;
+------+------+
| a1   | b1   |
+------+------+
|    1 |    1 |
|    2 |    2 |
|    3 |    3 |
+------+------+
3 rows in set (0.00 sec)

mysql> SELECT VERSION();
+-----------+
| VERSION() |
+-----------+
| 5.5.20    |
+-----------+
1 row in set (0.00 sec)

因此这适用于 auto_increment 和显式插入的值。你的问题一定出在其他地方