 check the constraint. Just more efficient in this sort of case.
&gt; &gt;You still need to know that a birth date is before an employment date
&gt; &gt;(but I do don't I?).
&gt; &gt;
&gt; &gt;MW: Don't get me wrong. I still think there is a killer app somewhere
&gt; &gt;in database meets ontology, but I know I don't want to get shot down
&gt; &gt;in flames suggesting something that can be done as well some existing
&gt; &gt;way.
&gt; &gt; &gt;
&gt; 
&gt; I'm puzzled by this perspective.  On the one hand, y