Question

我正在尝试从我的主表中删除记录，同时运行我理解的脚本，我主表中的Id在其他8个表中被引用为外键。我不想使用CASCADE DELETE，因为我必须改变表约束。我的主表名为Job，其主键为“Id”，在其他表中引用为外键“JobId”。

在从主Job表中删除之前，如何删除相关表中的外键引用记录。

这是我的下面的代码。评论的代码只是一个预测。

SELECT * FROM [JOB] j WHERE Name=@Name AND Title=@Title AND Zip=@Zip
                    AND Id<>@Id AND NOT EXISTS (SELECT * FROM NewJob nj WHERE J.Id=nj.Id)                           
                --DELETE FROM [Table1]  a WHERE a.JobId = j.Id AND
                --DELETE FROM [Table2]  F WHERE f.JobId = j.Id AND
                --DELETE FROM [Table3] jct WHERE jct.JobId = j.Id AND
                --DELETE FROM [Table4]  jch WHERE jch.JobId = j.Id AND
                --DELETE FROM [Table5]  jedu WHERE jedu.JobId = j.Id AND
                --DELETE FROM [Table6]  jexp WHERE jexp.JobId = j.Id AND
                --DELETE FROM [Table7]  jflc WHERE jflc.JobId = j.Id AND
                --DELETE FROM [Table8]  usj WHERE usj.JobId = j.Id AND
DELETE FROM [JOB] WHERE Id IN (SELECT Id FROM [JOB] WHERE Name=@Name AND Title=@Title AND Zip=@Zip AND Id<>@Id)

Answer 1

首先，您应该注意所有关系，然后您可以根据主查询中的键（ID）对引用的表运行DELETE语句。一个基本想法可能是：

-- how many tables and references? Just to be sure.
EXEC sp_fkeys 'Job'

-- required query for deleting relationships
DELETE FROM ForeignTable WHERE JobId IN (SELECT Id FROM Job WHERE [....])
DELETE FROM ForeignTable2 WHERE JobId IN (SELECT Id FROM Job WHERE [....])

-- main query
DELETE FROM [JOB] WHERE Id IN (SELECT Id FROM [JOB] WHERE Name=@Name AND Title=@Title AND Zip=@Zip AND Id<>@Id)

希望它有所帮助。

Answer 2

如果你创建一个临时表来存储你想要从主表中发现它们的id，那么这样的东西可能是最容易的。在事务中也要这样做，以维护ACID属性。

Begin Transaction
Create Table #JobIDsToDelete (JobID int);
Insert Into #JobIDsToDelete 
Select ID
  From [Job] As j
  Left Join NewJob As nj On j.ID = nj.ID
  Where Name = @Name
    And Title = @Title
    And Zip = @Zip
    And ID <> @ID
    And nj.ID Is Null;

Delete From Table1 Where JobID In (Select JobID From #JobIDsToDelete);
Delete From Table2 Where JobID In (Select JobID From #JobIDsToDelete);
...
Delete From [Job] Where ID In (Select JobID From #JobIDsToDelete);
Commit Transaction

使用外键从多个表中删除

2 个答案: