爲什麼我的觸發器不會觸發？

Question

我有如下表：現在

if object_id(N'dbo.Node') is null 
create table dbo.Node 
(
    ID bigint identity primary key, 
    ParentID bigint null foreign key references Node(ID) on delete no action, 
    DateCreated datetime not null, 
    LastUpdated datetime not null, 
    [Name] nvarchar(500) not null, 
); 

，因爲SQL Server時，我嘗試設置外鍵的級聯刪除，我創建了一個觸發做的工作抱怨：

create trigger Node_Delete on Node for delete 
as 
begin 
    delete from Node where ParentID in (select id from deleted) 
end 

現在，這裏是一個簡單的數據集：

ID     ParentID    DateCreated    LastUpdated    Name 
520     1     2010-01-12 02:26:26.890 2010-01-12 02:26:26.890 Test 1 
523     520     2010-01-12 02:32:44.777 2010-01-12 02:32:44.777 Test 2 

現在讓我們運行SQL的該位：

delete from Node where ID=520 

節點應該刪除，與子節點，該節點。那麼，爲什麼我會得到這個錯誤？

Msg 547, Level 16, State 0, Line 1 
The DELETE statement conflicted with the SAME TABLE REFERENCE constraint "FK__Node__ParentID__117F9D94". The conflict occurred in database "mydb", table "dbo.Node", column 'ParentID'. 
The statement has been terminated. 

Answer 1

外鍵會阻止初始刪除，並且觸發器不會觸發。嘗試使用INSTEAD OF觸發器從最遠的死者身上刪除。