try {
                Connection con = DriverManager.getConnection("jdbc:mysql://localhost/metairline", "root", "");
                PreparedStatement st;
                String sql = "INSERT INTO let(let_id, Od, Do, Datum) VALUES(?, ?, ?, ?)";
                st = con.prepareStatement(sql);
                st.setInt(1, Integer.parseInt(jTextField3.getText()));
                st.setString(2, jTextField2.getText().toString());
                st.setString(3, jTextField1.getText().toString());
                st.setString(4, jTextField3.getText().toString());
                st.execute();
                JOptionPane.showMessageDialog(null, "Uspesno ste dodali let!", "Dodavanje leta: ", JOptionPane.INFORMATION_MESSAGE);

            } catch (SQLException ex) {
                Logger.getLogger(Prijava.class.getName()).log(Level.SEVERE, null, ex);
            }