如何以编程方式备份​​SQL Server 2014 Express Localdb（.mdf）文件

Question

我有使用SQL Server 2014 LocalDB（ .mdf文件）的简单Windows应用程序。

而且我希望每当用户单击退出按钮时，我的应用程序都会自动将其localdb文件（ .mdf ）备份到用户同一台计算机上的另一个文件夹中。

我在下面编写了简单的代码，但是发生了SQLException语法错误：

''C：\\ greendb_angelheart.mdf'附近的语法不正确

（ DATABASE ""{0}""语法似乎不错）

而且我担心使用正常的SqlConnection代码连接到特定的localdb文件是否正确。

我的简单代码是：

private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
    if (MessageBox.Show("Really want to exit? Thank you !", MessageBoxButton.YesNo, MessageBoxImage.Warning) == MessageBoxResult.No)
    {
            e.Cancel = true;
    }
    else
    {
            string backuppath_basic = @"c:\Green_Backup";

            if (!System.IO.Directory.Exists("backuppath_basic"))
            {
                System.IO.Directory.CreateDirectory(backuppath_basic);
            }

            var greendbfileName = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), string.Format("greendb_{0}.mdf", personID));
            var copied_greendbfileName = string.Format(@"C:\greendb_{0}.mdf", personID);

            string localConnectionString = string.Format(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename= " + Environment.GetEnvironmentVariable("APPDATA") + @"\greendb_{0}.mdf;Integrated Security=True;Connect Timeout=30;", personID);

            SqlConnection backupConn = new SqlConnection();
            backupConn.ConnectionString = localConnectionString;
            backupConn.Open();

            SqlCommand backupcomm = backupConn.CreateCommand();
            string backupdb = @"BACKUP DATABASE ""{0}"" TO DISK '{1}'";
            backupdb = string.Format(backupdb, greendbfileName, copied_greendbfileName);

            SqlCommand backupcreatecomm = new SqlCommand(backupdb, backupConn);
            backupcreatecomm.ExecuteNonQuery();

            backupConn.Close();

            Environment.Exit(0);
        }
    }

Answer 1

经过多次尝试和分析，我终于解决了。 对于正在寻找解决方案的人，我的分享如下。

与其他数据库相比，使用MS SQL Localdb进行开发的人似乎更少。

数据库名称不必包括.mdf之类的扩展名，而等号=必须与DISK =一起使用

字符串backupdb = string.Format（@“ BACKUP DATABASE greendb_ {0} TO DISK ='c：\\ Green_Backup \\ greendb_ {0} .bak'”，personID）;

Answer 2

它可以帮助某人。

后备

try
{
    var dlg = new System.Windows.Forms.FolderBrowserDialog();
    var result = dlg.ShowDialog(this.GetIWin32Window());

    if (result.ToString() == "OK")
    {
        var dbfileName = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "LibraryManger.mdf");
        var backupConn = new SqlConnection { ConnectionString = eb.GetConnectionString() };
        backupConn.Open();

        var backupcomm = backupConn.CreateCommand();
        var backupdb = $@"BACKUP DATABASE ""{dbfileName}"" TO DISK='{Path.Combine(dlg.SelectedPath,"LibraryManagement.bak")}'";
        var backupcreatecomm = new SqlCommand(backupdb, backupConn);
        backupcreatecomm.ExecuteNonQuery();
        backupConn.Close();

        MessageBox.Show($"Database backup has successfully stored in {Path.Combine(dlg.SelectedPath, "LibraryManagement.bak")}", "Confirmation");
    }
}
catch (Exception ex)
{
    if(ex.Message.Contains("Operating system error"))
    {
        MessageBox.Show("Please chose a public folder.", "Error", MessageBoxButton.OK, MessageBoxImage.Error);
    }
    else
        MessageBox.Show(ex.Message, "Error", MessageBoxButton.OK, MessageBoxImage.Error);
}

恢复

恢复之前，您必须关闭现有连接

try
{
    if (eb != null)
    {
        eb.DisposeConnection();
        eb = null;
    }

    var dlg = new OpenFileDialog();
    dlg.InitialDirectory = "C:\\";
    dlg.Filter = "Database file (*.bak)|*.bak";
    dlg.RestoreDirectory = true;

    if (Equals(dlg.ShowDialog(), true))
    {
        using (var con = new SqlConnection())
        {
            con.ConnectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;Database=Master;Integrated Security=True;Connect Timeout=30;";
            con.Open();
            var dbfileName = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "LibraryManger.mdf");
                using (var cmd = new SqlCommand())
                {
                    cmd.Connection = con;
                    cmd.CommandText = $@"RESTORE DATABASE ""{dbfileName}"" FROM DISK='{dlg.FileName}'";

                    cmd.ExecuteNonQuery();
                }
                con.Close();
            }

        MessageBox.Show($"Database backup has successfully restored.", "Confirmation");
        eb = new EntityBroker.EntityBroker();
    }
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message, "Error", MessageBoxButton.OK, MessageBoxImage.Error);
}