Question

我希望有一个棘手的SQL语句作为每隔几分钟运行一次的事件。

当前，我正在使用Java，使用3条独立的语句在事务连接中执行顺序。

问：我不知道如何在没有Java的情况下构造这样的SQL语句。如果不可能只有一个SQL语句，那么我想使用事务处理（就像我在Java中使用的那样）并在这些单独的语句中的任何一个失败的情况下进行回滚。

我的案子： 我有3个表格：“ Factory”，“ Plan”，“ Machine”。我想做以下事情：

1.
WHERE Machines.annualCheck == "TRUE"
SET Machine.status = "IN_ANNUAL_CHECK"

For machines that got updated I need to do the following:

2.1 Update the related factory
WHERE Factory.id == Machine.linkFactoryID
UPDATE Factory.totalActiveMachines = --1

2.2 Delete the upcoming plans that planned to be handled by the related machine
DELETE rows WHERE Plan.willHandleByMachineID = Machine.ID

p.s。我正在使用MySQL

谢谢！

更新：

在遵循Simonare的建议之后，我很累地要做以下事情：

DELIMITER $

CREATE PROCEDURE annualCheck(IN Machine_ID int, IN Factory_ID int)
BEGIN
  UPDATE machine_table 
  SET machine_table.annualCheck = 'IN_ANNUAL_CHECK'
  WHERE machine_table.machine_id = Machine_ID;

  UPDATE factory_table
  SET factory_table.totalActiveMachines = factory_table.totalActiveMachines - 1
  WHERE factory_table.factory_id = Factory_ID;

  DELETE FROM plan_table WHERE plan_table.assign_to_machine = Machine_ID
END$

DELIMITER $$

BEGIN
    SELECT @m_id = machine_id, @f_id = link_factory_id
    FROM machine_table
    WHERE machine_table.annualCheck = 'TRUE';
END$$

CALL annualCheck(@m_id,@f_id)

我不知道为什么，但是我遇到了语法错误-一个接一个。这是我第一次使用PROCEDURE和DELIMITER。我做对了吗？

Answer 1

您可以使用存储过程

delimiter //

CREATE PROCEDURE myProc (IN Machine_ID int)
BEGIN
  UPDATE myTable 
  SET Machine.status = "IN_ANNUAL_CHECK"
  WHERE Machines.annualCheck == "TRUE";

  Update the related factory
  WHERE Factory.id == Machine.linkFactoryID
  UPDATE Factory.totalActiveMachines =  totalActiveMachines  -1;

  DELETE FROM Plan WHERE Plan.willHandleByMachineID = Machine_ID;
END//

然后您可以通过mysql

执行它

 CALL simpleproc(@a);

或来自Java

Answer 2

还可以在Machine表上创建触发器，如下所示：

CREATE TRIGGER `TRG_Machines_AfterUpdate` AFTER UPDATE ON `Machine` FOR EACH ROW BEGIN
    IF OLD.annualCheck = 'TRUE' AND NEW.annualCheck = 'IN_ANNUAL_CHECK' THEN
        UPDATE
            Factory
        SET
            totalActiveMachines = totalActiveMachines - 1
        WHERE
            id = NEW.linkFactoryID
        ;

        DELETE FROM
            Plan
        WHERE
            willHandleByMachineID = NEW.ID
        ;
    END;
END

因此您可以发出常规更新：

UPDATE Machine SET annualCheck = 'IN_ANNUAL_CHECK' WHERE annualCheck = 'TRUE'

SQL事件-在更新其他表之后删除和更新表上的行

2 个答案: