如何从包含自引用外键的表中删除所有数据 [英] How to Delete all data from a table which contain self referencing foreign key

问题描述

我有一个在其内部定义了员工关系的表。
ie

  EmpID名称SeniorId 
 -------------- --------- 
 1 A NULL 
 2 B 1 
 3 C 1 
 4 D 3 
  

等等...

其中，高级ID是其主键表相同的外键with refrence column EmpId
我要清除此表中的所有行，而不删除任何约束。我如何做到这一点？

删除需要执行如下
4，3，2，1

$ b b

我如何做这

Jhonny的回答

解决方案

我不知道我是否缺少某些东西，但是也许你可以试试这个。

  UPDATE employee SET SeniorID = NULL 
 DELETE FROM employee 
  

I have a table which has employee relationship defined within itself. i.e.

EmpID   Name  SeniorId
-----------------------
1         A      NULL
2         B       1
3         C       1
4         D       3

and so on...

Where Senior ID is a foreign key whose primary key table is same with refrence column EmpId I want to clear all rows from this table without removing any constraint. How can i do this?

Deletion need to be performed like this 4, 3 , 2 , 1

How can I do this

EDIT:

Jhonny's Answer is working for me but which of the answers are more efficient.

解决方案

I don't know if I am missing something, but maybe you can try this.

UPDATE employee SET SeniorID = NULL
DELETE FROM employee

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