临时表的主键已经存在

I have the following query

我有以下查询。

declare @var1 int, @var2 int
set @var1 = 110
set @var2 = 300

IF object_id('tempdb..#tbl_Contract') IS NOT NULL
BEGIN
   ALTER TABLE #tbl_Contract drop constraint PK_#tbl_Contract
   DROP TABLE #tbl_Contract
END

CREATE TABLE #tbl_Contract
(  ContractID int NOT NULL
,  PersonID int NOT NULL
,  EndDate smalldatetime NULL
,  CONSTRAINT [PK_#tbl_Contract] PRIMARY KEY CLUSTERED 
   (
     ContractID ASC
   )
)
...
declare