Question

我写了一个触发器，在对表a执行操作后向表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，则它确实有效。

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，仁

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，我在简化测试中重现了你的情况。两者，使用触发表中的结果插入引用新行alreay并使用NEW值直接插入工作正常

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 ;

触发触发器

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结果中插入

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。你的问题必须在其他地方

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

1 个答案: