有時候需要清除一些資料，但是總會有一些外來鍵關聯多加阻攔，下面是一些外來鍵關聯查詢，方便更快捷有效的查詢到需要處理的外來鍵資訊。

一、外來鍵資訊

查詢列從左到右分別是： 外來鍵約束名，子表名，外來鍵列名，父表名

 --外來鍵資訊
select fk.name fkname , ftable.name ftablename, cn.name fkcol, rtable.name ftablename,ObjectProperty(fk.id,'CnstIsUpdateCascade') updatCase,ObjectProperty(fk.id,'CnstIsDeleteCascade') deletCase from
 
 sysforeignkeys
join sysobjects fk
on sysforeignkeys.constid = fk.id
join sysobjects ftable
on sysforeignkeys.fkeyid = ftable.id
join sysobjects rtable
on sysforeignkeys.rkeyid = rtable.id
join syscolumns cn
on sysforeignkeys.fkeyid = cn.id and sysforeignkeys.fkey = cn.colid

二、外來鍵被參考表

 1 --外來鍵被參考表
 
 2 SELECT 主鍵列ID=b.rkey
 3 ,主鍵列名=(SELECT name FROM syscolumns WHERE colid=b.rkey AND id=b.rkeyid)
 4 ,外來鍵表ID=b.fkeyid
 5 ,外來鍵表名稱=object_name(b.fkeyid)
 6 ,外來鍵名稱= c.name
 7 ,外來鍵列ID=b.fkey
 8 ,外來鍵列名=(SELECT name FROM syscolumns WHERE colid=b.fkey AND id=b.fkeyid)
 9 ,級聯更新=ObjectProperty(a.id,'CnstIsUpdateCascade
 
')
10 ,級聯刪除=ObjectProperty(a.id,'CnstIsDeleteCascade')
11 FROM sysobjects a
12 join sysforeignkeys b on a.id=b.constid
13 join sysobjects c on a.parent_obj=c.id
14 join syscolumns cn
15 on b.fkeyid = cn.id and b.fkey = cn.colid
16 where a.xtype='f' AND c.xtype='U'
17 and object_name(b.rkeyid)='dt_article'

三、外來鍵詳細資訊

參考來源http://technet.microsoft.com/zh-cn/library/ms190196(v=SQL.110).aspx

 1 --外來鍵詳細資訊
 2 SELECT
 3 f.name AS foreign_key_name
 4 ,OBJECT_NAME(f.parent_object_id) AS table_name
 5 ,COL_NAME(fc.parent_object_id, fc.parent_column_id) AS constraint_column_name
 6 ,OBJECT_NAME (f.referenced_object_id) AS referenced_object
 7 ,COL_NAME(fc.referenced_object_id, fc.referenced_column_id) AS referenced_column_name
 8 ,is_disabled
 9 ,delete_referential_action_desc
10 ,update_referential_action_desc
11 FROM sys.foreign_keys AS f
12 INNER JOIN sys.foreign_key_columns AS fc
13 ON f.object_id = fc.constraint_object_id
14 WHERE f.parent_object_id = OBJECT_ID('test');

文章轉載自：https://www.cnblogs.com/guanshan/p/guan131.html