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]
*/