问检查两个以上值的重复项，如果没有重复项，则插入查询

EN

try
        {
        Connection connection=DriverManager.getConnection("jdbc:mysql://localhost:3306/testing","root","");

    //block of code to check user exists or not.
    //Statement statement = connection.createStatement();
    PreparedStatement Pstatement;

    String query = "select Name,Email from detail";
    PreparedStatement ps = connection.prepareStatement(query);
    ResultSet rs = ps.executeQuery() ;


    if(rs.next())
    {
        //from database
        String name_db1 = rs.getString("Name").trim(); //using trim removes all white spaces
        String email_db2 = rs.getString("Email").trim();

        //from user GUI
        String entered_name = name.getText().trim(); //using trim removes all white spaces
        String entered_email = email.getText().trim();

        boolean valid = true;

        if(entered_name.equals(""))
        {
            JOptionPane.showMessageDialog(null,"Enter name");
            valid = false;
        }
        else if(name_db1.equals(entered_name))
        {
            JOptionPane.showMessageDialog(null,"Enter name taken");
            name.setText(null);
            valid = false;
        }
        else if(entered_email.equals(""))
        {
            JOptionPane.showMessageDialog(null,"Enter email");
            valid = false;
        }
        else if(email_db2.equals(entered_email))
        {
            JOptionPane.showMessageDialog(null,"email taken");
            email.setText(null);
            valid = false;
        }
        else if(valid == true)
        {
            Pstatement=connection.prepareStatement("insert into detail values(?,?)");

            //Specifying the values of preparestatement parameter                  
            Pstatement.setString(1,name.getText());
            Pstatement.setString(2,email.getText());
            Pstatement.executeUpdate();
            JOptionPane.showMessageDialog(null,"registration successful");  
            //x++;
        }

    }
    else
    {
        //incase if the user click without filling up the fields
        JOptionPane.showMessageDialog(null,"not yet registered"); 
    }
    }
    catch(SQLException e)
    {
        e.printStackTrace();
    }