How to restore a database from C#

Question

I have a SQL 2008 DB. I am running a form that backs that DB up, then tries to update it. If the update fails the idea is to restore that backup. Here is the code I am using to restore the backup.

public void RestoreDatabase(String databaseName, String backUpFile, String serverName, String userName, String password)
{
    Restore sqlRestore = new Restore();
    BackupDeviceItem deviceItem = new BackupDeviceItem(backUpFile, DeviceType.File);
    sqlRestore.Devices.Add(deviceItem);
    sqlRestore.Database = databaseName;
    ServerConnection connection = new ServerConnection(serverName, userName, password);
    Server sqlServer = new Server(connection);
    sqlRestore.Action = RestoreActionType.Database;

    string logFile = System.IO.Path.GetDirectoryName(backUpFile);
    logFile = System.IO.Path.Combine(logFile, databaseName + "_Log.ldf");

    string dataFile = System.IO.Path.GetDirectoryName(backUpFile);
    dataFile = System.IO.Path.Combine(dataFile, databaseName + ".mdf");

    Database db = sqlServer.Databases[databaseName];
    RelocateFile rf = new RelocateFile(databaseName, dataFile);
    sqlRestore.RelocateFiles.Add(new RelocateFile(databaseName, dataFile));
    sqlRestore.RelocateFiles.Add(new RelocateFile(databaseName + "_log", logFile));
    sqlRestore.SqlRestore(sqlServer);
    db = sqlServer.Databases[databaseName];
    db.SetOnline();
    sqlServer.Refresh();
}

The issue seems to be that the file names I pick are different from the online DB. I basically want to replace the database on the server with the backup. I get an exception when I call SqlRestore.

The main exception says

{"Restore failed for Server 'localhost'. "}

Digging into the inner exceptions shows these errors

An exception occurred while executing a Transact-SQL statement or batch.

and then

Logical file 'DB' is not part of database 'DB'. Use RESTORE FILELISTONLY to list the logical file names.\r\nRESTORE DATABASE is terminating abnormally.

I assume there is some way to tell this to just use replace the existing DB as is.

I use this bit of code to get the file path of the DB to have a directory to dump the backup. Maybe this could be used to get the file names to recreate.

public string GetDBFilePath(String databaseName, String userName, String password, String serverName)
{
    ServerConnection connection = new ServerConnection(serverName, userName, password);
    Server sqlServer = new Server(connection);
    Database db = sqlServer.Databases[databaseName];
    return sqlServer.Databases[databaseName].PrimaryFilePath;
}

Answer 1

I changed my back up and restore functions to look like this:

public void BackupDatabase(SqlConnectionStringBuilder csb, string destinationPath)
{
    ServerConnection connection = new ServerConnection(csb.DataSource, csb.UserID, csb.Password);
    Server sqlServer = new Server(connection);

    Backup bkpDatabase = new Backup();
    bkpDatabase.Action = BackupActionType.Database;
    bkpDatabase.Database = csb.InitialCatalog;
    BackupDeviceItem bkpDevice = new BackupDeviceItem(destinationPath, DeviceType.File);
    bkpDatabase.Devices.Add(bkpDevice);
    bkpDatabase.SqlBackup(sqlServer);
    connection.Disconnect();

}

public void RestoreDatabase(String databaseName, String backUpFile, String serverName, String userName, String password)
{
    ServerConnection connection = new ServerConnection(serverName, userName, password);
    Server sqlServer = new Server(connection);
    Restore rstDatabase = new Restore();
    rstDatabase.Action = RestoreActionType.Database;
    rstDatabase.Database = databaseName;
    BackupDeviceItem bkpDevice = new BackupDeviceItem(backUpFile, DeviceType.File);
    rstDatabase.Devices.Add(bkpDevice);
    rstDatabase.ReplaceDatabase = true;
    rstDatabase.SqlRestore(sqlServer);
}

That way they just use whatever files are there. There are no longer and directives to relocate files.

Answer 2

Thanks Remus for your answer!

I have modified

sqlRestore.RelocateFiles.Add(new RelocateFile(databaseName, dataFileLocation));
sqlRestore.RelocateFiles.Add(new RelocateFile(databaseName + "_log", logFileLocation)); 

these two lines to

System.Data.DataTable logicalRestoreFiles = sqlRestore.ReadFileList(sqlServer);
sqlRestore.RelocateFiles.Add(new RelocateFile(logicalRestoreFiles.Rows[0][0].ToString(), dataFileLocation));
sqlRestore.RelocateFiles.Add(new RelocateFile(logicalRestoreFiles.Rows[1][0].ToString(), logFileLocation));

and my code is running successfully.

Thanks for the support!