 <p>Further to @richard-pawson's answer, I've ported the "table-of-two-halves" pattern from Entity Framework to Java (JDO/DataNucleus), with a complete example up on <a href="https://github.com/isisaddons/isis-module-poly" rel="nofollow">github</a>.</p> <p>You should be able to use it to come up with something similar back in .NET land.</p>