It’s a little example, or may be template, of correct code for work with MSSQL server using OleDbConnection. There are two parts you should remember about - connection string and OleDB commands. The most difficult part of this is the connection string. It took me a lot of my time until I studied how to write this string easily.

I have a "secret" knowledge how easily write the text of connection string and even to try it. This post is for registered users only (https://markimarta.com/c/how-easily-write-the-text-of-connection-string/).

Below is the part of C# code to work with OleDbCommand:

static string connSQL = "Provider=SQLOLEDB.1;Password=Pass@word1;Persist Security Info=False;User ID=searchUser;Initial Catalog=ArchiveDB;Data Source=sqlserver\\DBName";

string sqlCommand = String.Format(@"SELECT ID, message FROM mytable WHERE ID = '{0}'  ORDER by ID desc", "123");


      OleDbConnection oledbCnn = new OleDbConnection(connSQL);
        string tableContent = "";
        try
        {
            oledbCnn.Open();
            OleDbCommand cmd = new OleDbCommand(sqlCommand, oledbCnn);
            cmd.CommandTimeout = 150;
            OleDbDataReader reader = cmd.ExecuteReader();
            while (reader.Read()) 
            {  
                reader.GetValue(1);
            }
            reader.Close();
        }
        catch(Exception ex)
        {
            
        }
        finally
        {
            oledbCnn.Close();
        }