如何在代码中分离LocalDB(SQL Server Express)文件

在部署中使用LocalDB .mdf文件时,您通常需要移动,删除或备份数据库文件.
首先将此文件分离为 simply deleting it will cause errors because LocalDB still keeps a registration of it是至关重要的.

那么如何在代码中分离LocalDB .mdf文件？

解决方法

''' <summary>
''' Detach a database from LocalDB. This MUST be done prior to deleting it. It must also be done after a inadvertent (or ill advised) manual delete.
''' </summary>
''' <param name="dbName">The NAME of the database,not its filename.</param>
''' <remarks></remarks>
Private Sub DetachDatabase(dbName As String)
    Try
        'Close the connection to the database.
        myViewModel.CloseDatabase()

        'Connect to the MASTER database in order to excute the detach command on it.
        Dim connectionString = String.Format("Data Source=(LocalDB)v11.0;Initial Catalog=master;Integrated Security=True")
        Using connection As New SqlConnection(connectionString)
            connection.Open()
            Dim cmd = connection.CreateCommand
            '--Before the database file can be detached from code the workaround below has to be applied.
            'http://web.archive.org/web/20130429051616/http://gunnalag.wordpress.com/2012/02/27/fix-cannot-detach-the-database-dbname-because-it-is-currently-in-use-microsoft-sql-server-error-3703
            cmd.CommandText = String.Format("ALTER DATABASE [{0}] SET OFFLINE WITH ROLLBACK IMMEDIATE",dbName)
            cmd.ExecuteNonQuery()
            '--
            '--Now detach
            cmd.CommandText = String.Format("exec sp_detach_db '{0}'",dbName)
            cmd.ExecuteNonQuery()
            '--
        End Using
    Catch ex As Exception
        'Do something meaningful here.    
    End Try
End Sub

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