Java Database Connectivity (JDBC)

Hi all.

I heard about PreparedStatement's performance in this cases:

            PreparedStatement ps = c.prepareStatement("update people set first_name = ?, last_name = ?, gender = ?, email = ? where id_people = ?");
            while(au.hasNext()) {
                     ps.setString(1,first_name);
                     ps.setString(2, last_name);
                     ps.setString(3, gender);
                     ps.setString(4, email);
                     ps.setInt(5, id);
            }

one of the advantages is that the PreparedStatement is only compiled once and the query is executed N-times... but, what's the performance difference in this case:

            PreparedStatement ps = null;
            while(au.hasNext()) {
                     ps = c.prepareStatement("update people set first_name = ?, last_name = ?, gender = ?, email = ? where id_people = ?");
                     ps.setString(1,first_name);
                     ps.setString(2, last_name);
                     ps.setString(3, gender);
                     ps.setString(4, email);
                     ps.setInt(5, id);
            }

other questions emerge in my head, if i redefine a PreparedStatement for example:

            PreparedStatement ps = c.preparedStatement("insert into bla bla");
            ps.executeUpdate();
            while(au.hasNext()) {
                    if(odd) {
                         ps = c.prepareStatement("insert into bla bla bla");
                         ps.executeUpdate();
                    } else {
                         ps = c.prepareStatement("delete from bla bla bla");
                         ps.executeUpdate();
                    }
                    ps = c.prepareStatement("select from bla bla bla");
                    rs = ps.executeQuery();
            }

I will apreciate all your comments about this,

Kind regards.

JAEC