c# mysql

MySqlConnection ,  MySqlDataReader, MySqlCommand

how can w know what those function mean and what they do if i want to write some thing to mysql databate such as update I can put sql statement to  MySqlCommand or not

private void button1_Click(object sender, EventArgs e)
        {
            string MyConString = "SERVER=localhost;" +
                "DATABASE=registration;" +
                "UID=root;" +
                "PASSWORD='';";
            MySqlConnection connection = new MySqlConnection(MyConString);
            MySqlCommand command = connection.CreateCommand();
            MySqlDataReader Reader;
            command.CommandText = "select * from teera";
            connection.Open();
            Reader = command.ExecuteReader();
            while (Reader.Read())
            {
                string thisrow = "";
                for (int i = 0; i < Reader.FieldCount; i++)
                    thisrow += Reader.GetValue(i).ToString() + ",";
                listBox1.Items.Add(thisrow);
                System.IO.File.AppendAllText(@"C:\file.txt", "thisrow");

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