判断是否存在

1 判断数据库是否存在

if exists (select * from sys.databases where name = '数据库名')  
  drop database [数据库名]  
if exists (select * from sys.databases where name = '数据库名')
  drop database [数据库名]
2 判断表是否存在
if exists (select * from sysobjects where id = object_id(N'[表名]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)  
  drop table [表名]  
if exists (select * from sysobjects where id = object_id(N'[表名]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
  drop table [表名]
3 判断存储过程是否存在
if exists (select * from sysobjects where id = object_id(N'[存储过程名]') and OBJECTPROPERTY(id, N'IsProcedure') = 1)  
  drop procedure [存储过程名]  
if exists (select * from sysobjects where id = object_id(N'[存储过程名]') and OBJECTPROPERTY(id, N'IsProcedure') = 1)
  drop procedure [存储过程名]
4 判断临时表是否存在
if object_id('tempdb..#临时表名') is not null    
  drop table #临时表名  
if object_id('tempdb..#临时表名') is not null  
  drop table #临时表名 
5 判断视图是否存在
--SQL Server 2000   
IF EXISTS (SELECT * FROM sysviews WHERE object_id = '[dbo].[视图名]'  
--SQL Server 2005   
IF EXISTS (SELECT * FROM sys.views WHERE object_id = '[dbo].[视图名]'  
--SQL Server 2000
IF EXISTS (SELECT * FROM sysviews WHERE object_id = '[dbo].[视图名]'
--SQL Server 2005
IF EXISTS (SELECT * FROM sys.views WHERE object_id = '[dbo].[视图名]'
6 判断函数是否存在
--  判断要创建的函数名是否存在    
  if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[函数名]') and xtype in (N'FN', N'IF', N'TF'))    
  drop function [dbo].[函数名]    
--  判断要创建的函数名是否存在  
  if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[函数名]') and xtype in (N'FN', N'IF', N'TF'))  
  drop function [dbo].[函数名]  

IF  EXISTS (SELECT * FROM sys.views WHERE object_id = OBJECT_ID(N'[dbo].[vMD_ProjectAdd]'))
DROP VIEW [dbo].[vMD_ProjectAdd]
GO