How to parse values for the result set's .equals function?

Question

image showing my jFrame

I am making a frame which shows records in the sql table one-by-one using text fields as shown. While writing the code for the next button, I need to know the position of the result set to go to the next record. For this purpose, I used a do-while loop with an "if" condition. Following is my code:

try{
        Connection conn=null;
        Statement stmt=null;
        ResultSet rs=null;
        String url="jdbc:mysql://localhost/MYORG", userid="root", pwd="shreyansh";
        conn=DriverManager.getConnection(url,userid,pwd);
        stmt=conn.createStatement();
        String query="select * from emp;";
        rs=stmt.executeQuery(query);
        String search=jTextField1.getText();
        String search1=jTextField2.getText();
        double search2=Double.parseDouble(jTextField3.getText());
        String search3=jTextField3.getText();
        rs.first();
        do{
            if(rs.equals(new Object[] {search, search1, search2, search3}))
                break;
        }while(rs.next());
        rs.next();
        String nm=rs.getString("Name");
        String desg=rs.getString("Designation");
        double pay=rs.getDouble("Pay");
        String city=rs.getString("City");
        jTextField1.setText(nm);
        jTextField2.setText(desg);
        jTextField3.setText(pay + "");
        jTextField4.setText(city);
    }catch(Exception e){
        JOptionPane.showMessageDialog(null, e.getMessage());
    }

But it shows an error "after end of Result Set". Please help me with this. Any suggestions to make my code better are also welcome. Thanks in Advance!!

Answer 1

You can't use ResultSet.equals for this, because that is not what the Object.equals contract is for. It is for checking if an object is equal to another object of the same (or at least compatible) type. A ResultSet will therefor never be equal to an array of object values.

It looks like you want to select a single row from the emp table that matches your search values, in that case the correct solution is to ask the database for only that row. Selecting all rows and then filtering in your Java application is very inefficient, because the database has to send all rows to your application, while finding data is exactly what a database is good at.

Instead, you should use a where clause with a prepared statement:

try (Connection connection = DriverManager.getConnection(url, userid, pwd);
     PreparedStatement pstmt = connection.prepareStatement(
         "select * from emp where Name = ? and Designation = ? and Pay = ? and City = ?")) {
   pstmt.setString(1, search);
   pstmt.setString(2, search1);
   pstmt.setDouble(3, search2);
   pstmt.setString(4, search3);
   try (ResultSet rs = pstmt.executeQuery()) {
       if (rs.next() {
           String nm = rs.getString("Name");
           String desg = rs.getString("Designation");
           double pay = rs.getDouble("Pay");
           String city = rs.getString("City");
           jTextField1.setText(nm);
           jTextField2.setText(desg);
           jTextField3.setText(String.valueOf(pay));
           jTextField4.setText(city);
       } else {
           // handle not found case
       }
   } 
}