private void button3_Click(object sender, EventArgs e)
 {
     string q = "INSERT INTO LOTY(";
     q += "data_wylotu,";
     q += "czas_lotu,";
     q += "lotnisko_docelowe,";
     q += "lotnisko_zrodlowe,";
     q += "samolot) ";
     q += "VALUES(";
     q += "'" + NFdate.Text + "',";
     q += NFtime.Text + ",";
     q += NFdest.Text + ",";
     q += NFsrc.Text + ",";
     q += NFplane.Text + ");";
     CommonQuery cq = new CommonQuery(q);
     if (dataBase.executeInsert(cq))
     {
         MessageBox.Show("Lot został poprawnie dodany.");
     }
 }
 private void button2_Click(object sender, EventArgs e)
 {
     string q = "INSERT INTO REZERWACJE(";
     q += "ID_KLIENTA,";
     q += "ID_LOTU,";
     q += "KLASA) ";
     q += "VALUES(";
     q += NRclient.Text + ",";
     q += NRflight.Text + ",";
     q += "'" + NRclass.SelectedItem + "');";
     CommonQuery cq = new CommonQuery(q);
     if (dataBase.executeInsert(cq))
     {
         MessageBox.Show("Rezerwacja została poprawnie dodana.");
     }
 }