自动生成清空数据库的SQL语句

有时候需要把数据库中表记录都删除掉，为了方便我们有必要制作一个清空数据库的脚本，
这里主要是考虑存在外键约束，和标识列问题。
存在外键关系时候就要查询出，先要删除哪一张表，后要删除哪一张表，
当存在标识列的时候，就要DBCC Checkident 来重新设置标识值。

Declare   @Sql   nvarchar ( Max )
; With  T1
As
(
     Select      Convert ( int , 0 )  as  LevelNo,fkeyid,rkeyid
     From  sys.sysforeignkeys a
     Where   Not   Exists ( Select   1   From  sys.sysforeignkeys  Where  rkeyid = a.fkeyid)
     Union   All
     Select  b.LevelNo + 1 ,a.fkeyid,a.rkeyid
     From  sys.sysforeignkeys a,T1 b
     Where  a.fkeyid = b.rkeyid
) 
,T2
As
(
     Select  LevelNo,id = fkeyid  From  T1
     Union   All
     Select  LevelNo + 1 ,rkeyid  From  T1
)
,T3
As
(
     Select  a.name,LevelNo = Max ( Isnull (b.LevelNo, 0 )),c.is_identity 
     From  sys.sysobjects a
     Left   Outer   Join  T2 b  On  a.id = b.id 
     Left   Outer   Join  sys.identity_columns c  On  c. object_id = a.id
     Where   a.xtype = ' U '   And  a.name <> ' sysdiagrams '
     Group   By   a.name,c.is_identity
    
)
Select   @Sql = Isnull ( @Sql , ' Use ' + Quotename ( Db_name ())) + char ( 13 ) + char ( 10 ) +
         Case      When  LevelNo = 0   Then   ' Truncate Table  ' + Quotename (name)
                 When  is_identity = 1   Then   ' Delete From  ' + Quotename (name) + '  DBCC Checkident ( ''' + Quotename (name) + ''' ,Reseed,0) '
                 Else   ' Delete From  ' + Quotename (name)  End
From  T3
Order   By  LevelNo
Print   @Sql

生成示例
e.g:

/*
Use[Test]
Truncate Table [os]
Truncate Table [T2]
Truncate Table [t4]
Truncate Table [t5]
Truncate Table [test]
Delete From [T3]
Delete From [T1]
*/