String ConnectionString = null;
            MySqlConnection cnn;
            ConnectionString = "server=localhost;database=librarydb;uid=root;pwd=admin;";
            cnn = new MySqlConnection(ConnectionString);
            MySqlDataAdapter comm1 = new MySqlDataAdapter("SELECT COUNT(*) FROM dbaccounts WHERE username ='" + txtUsername.Text + "'AND password='" + txtPassword.Text + "'", cnn);//query

            GlobalVariables.username = txtUsername.Text;
            GlobalVariables.password = txtPassword.Text;

            DataTable dt = new DataTable();//virtual table
            comm1.Fill(dt);
            try
            {
                cnn.Open();
                if (dt.Rows[0][0].ToString() == "1")
                {
                    this.Hide();
                    LoginSuccess frmSuccess = new LoginSuccess();
                    frmSuccess.Show();

                }
                else
                {
                    LoginFailed frmFailed = new LoginFailed();
                    frmFailed.Show();
                }