使用 C# 的 SQL Server 数据库备份进度

Question

My requirement is to:

1. Programmatically take backup of SQL Server databases using a SQL script
2. Monitor the progress (for this I have a script)

I have this code:

protected void  Backup_click(object sender, EventArgs e)
{
    var sqlQuery = "EXEC  [Test].[dbo].[Usp_Test_Backup_Database] @BackupLabel = 'DB_TEST_1_18_PostScript'";

    using (var connection = new SqlConnection(ConnectionString))
    {
        await connection.OpenAsync();

        using (var tran = connection.BeginTransaction())
        {
            using (var command = new SqlCommand(sqlQuery, connection, tran))
            {
                try
                {
                    await command.ExecuteNonQueryAsync();
                }
                catch (Exception)
                {
                    tran.Rollback();
                    throw;
                }

                tran.Commit();
            }
        }
    }
}

This takes the backup. Usually I SSMS to my server, and execute back up progress script which has field - PERCENTAGE (10, 20, 34, 70. etc)

Running with multiple thoughts:

1. Create a new button on my UI and execute progress scripts, read the percentage values and update the value in some label?

2. Or include one more CMD statement to execute backup scripts along with the backup code?

Any suggestions?

Answer 1

You can send messages from SQL Server to your Applicatio using PRINT or RAISERROR . If you need to ensure the message is going to be send you should use RAISEERROR and NOWAIT:

RAISERROR (N'working', 10,1) WITH NOWAIT

The Format is as follows as stated in the docs :

RAISERROR (N'This is message %s %d.', -- Message text.  
           10, -- Severity,  
           1, -- State,  
           N'number', -- First argument.  
           5); -- Second argument.  
-- The message text returned is: This is message number 5.  

You can then subscribe to the message events by using the InfoMessage event of your SqlConnection .

var sqlQuery = @"RAISERROR (N'working', 10,1) WITH NOWAIT";

using (var connection = new SqlConnection(@"Server=localhost\SQLExpress;Database=master;Trusted_Connection=True;"))
{
    await connection.OpenAsync();

    connection.InfoMessage += (sender, args) => 
    {
        foreach (var element in args.Errors.OfType<SqlError>())
        {
            Console.WriteLine($"Class: {element.Class} LineNumber: {element.LineNumber} Message: {element.Message} Number: {element.Number} Procedure: {element.Procedure}");
        }
    };

    using (var command = new SqlCommand(sqlQuery, connection))
    {
        await command.ExecuteNonQueryAsync();
    }
}

Note that SQL Server sends information messages it self and that you can also define your own messages . When a message it of type error the client connection is going to be closed sooner or later so you need to be a little careful what type of message you choose for your own messages.