private void btn_cancel_ticket_Click(object sender, EventArgs e)
{
string sql = null, member = null, P_id;
methods m = new methods();
sql = "select Ticket.P_id from Ticket where Ticket.T_id='" + textBox_ticket_no.Text + "' ";
member = "P_id";
P_id = m.id_sender(sql, member);
sql = "DELETE FROM Ticket WHERE Ticket.T_id='" + textBox_ticket_no.Text + "'";
m.delete_row(sql);
sql = "DELETE FROM Passenger WHERE P_id='" + P_id + "'";
m.delete_row(sql);
MessageBox.Show("Ticket Cancled");
}