Question

I am trying to use JDBC and my query is working in some cases but not working in others.
I would really appreciate any help.

Some of my code:

public Result getSpecificTopic()
    {
        String query = "Select msg_body, msg_author from lawers_topic_msg";// where msg_id=2 order by msg_id desc";
         try
        {
            con = mysql.getConnection();
            //Statement stmt = con.createStatement();
            PreparedStatement stmt = con.prepareStatement(query);
            //stmt.setInt(1, topicId);
            ResultSet rs = stmt.executeQuery(query);
            int rowCount = rs.getRow();
            specificTopic = ResultSupport.toResult(rs);

            con.close();
            stmt.close();
        }
        catch(Exception e)
        {
        }
        return this.specificTopic;
    }

    public void setTopicId(String num)
    {
        this.topicId = Integer.parseInt(num);
    }

    public int getTopicId()
    {
        return this.topicId;
    }

However if i change

String query = "Select msg_body, msg_author from lawers_topic_msg";

to the

String query = "Select msg_body, msg_author from lawers_topic_msg where msg_id = " + topicId; 

Then the resultset retunrs nothing….
I am breaking my head here and still cannot figure out what is the problem

Answer 1

As a first step, it’d be worth making sure an exception’s not being thrown – at the very least log something in your catch() block.

Also be worth logging the SQL generated, and making sure that actually returns what you expect from the database when running it directly.

If you have multiple databases, it’d be worth confirming you’re running against the one you think you are – I’m embarrassed to admit I’ve been caught out that way before.