Error: "Database 'XXX' is already open and can only have one user at a time"

要打开一个数据库看属性的时候发生错误

Error 22285: [SQL-DMO]Database 'CORE' is already open and can only
have one user at a time.

新建一个查询，输入

use master
go
sp_who2

找到连接到XXX数据库的spid

kill <spid>;

成功以后

alter database CORE set multi_user;