我的数据库显示为只读。所以我尝试将数据库只读属性更改为False(databae->rightclik->property-option->database Readonly=>false）后单击确定按钮得到一些错误：
Alter failed for Database 'Vallett'.
Unable to open the physical file "C:\Program Files (x86)\Microsoft SQL Server\MSSQL.1\MSSQL\Backup\Vallett.mdf". Operating system error 5: "5(Access is denied.)".
Unable to open the physical file "C:\Program Files (x86)\Microsoft SQL Server\MSSQL.1\MSSQL\Backup\Vallett_1.ldf". Operating system error 5: "5(Access is denied.)".
Database 'Vallett' cannot be opened due to inaccessible files or insufficient memory or disk space. See the SQL Server errorlog for details.
ALTER DATABASE statement failed. (Microsoft SQL Server, Error: 5120)