怎么判断sql数据库是不是存在，存在删除

Posted 2023-03-26

参考技术A

判断数据库，如果存在则删除：

IF (EXISTS(SELECT * FROM master.dbo.sysdatabases WHERE dbid=db_ID('dbname')))

DROP DATABASE dbname

如果提示：删除数据库时提示数据库正在被使用，无法删除(Cannot drop database databasename because it is currently in use)，使用：

IF (EXISTS(SELECT * FROM master.dbo.sysdatabases WHERE dbid=db_ID('dbname')))

BEGIN

USE master

ALTER DATABASE dbname

SET single_user

WITH ROLLBACK IMMEDIATE

DROP DATABASE dbname

END

扩展资料

判断储存过程,如果存在则删除

IF (EXISTS(SELECT * FROM sysobjects WHERE name='procedurename' AND type='P'))

DROP PROCEDURE procedurename

判断触发器,如果存在则删除

IF (EXISTS(SELECT * FROM sysobjects WHERE id=object_id(N'[dbo].[triggername]') AND OBJECTPROPERTY(id, N'IsTrigger') = 1))

DROP TRIGGER triggername

判断用户函数是否存在,如果存在则删除

此处type有两种: 'TF'- Table-Value Function 表值函数 'FN'- Scalar-Value Function 标量值函数

IF (EXISTS(SELECT * FROM sysobjects WHERE id=object_id(N'[dbo].[userfunction]') AND (type='FN' OR type='TF')))

DROP FUNCTION userfunction