Question

I am having a java class where I am executing a query and assigning the query result to an string array, finally return the array.

Everything works fine. But I want to return “no data” if the db values are empty (not the whole array). what can I do for this?

Code:

query="select `t1`,`t2`,`t3` from test";

                PreparedStatement pre = conn.prepareStatement(query);
                ResultSet res = pre.executeQuery();
                String val[][] = new String[res.getRow()][3];
           while (res.next()) {
                val[i][0] = res.getString(1);
                val[i][1] = res.getString(2);
                val[i][2] = res.getString(3);
                i++;
              }

                res.close();
                conn.close();
                pre.close();

                return (val);

(Where I want the val[1][1] to be “No Data” if res.getString(2) is null).

Answer 1

No Data seems to be a value you display more than a logical value.

So you should decide of a special value and display it in a special way. We usually call this a sentry value.

This value could be null or a string that can’t be in your db. (maybe it doesn’t apply here as everything is often possible in a db).

Also note that it could be attractive to use an exception instead of this special value but it is actually a very poor use of exceptions, mostly for performance issues and hence it is a design to avoid if possible except if this value can lead to problems for your clients classes.