ignKey</pre>
<div class="block">(Optional) Used to specify or control the generation of a
   foreign key constraint for the columns corresponding to the
   <code>pkJoinColumns</code> element when table generation is
   in effect.  If both this element and the
   <code>foreignKey</code> element of any of the
   <code>pkJoinColumns</code> elements are specified, the
   behavior is undefined.  If no foreign key annotation element
   is specified in either location, the persistence provider's
   default foreign