ation of the domain represented by a column in a relation; a role</div>
</td>
</tr>
<tr class="altColor">
<th class="colFirst" scope="row"><a href="ForeignKey.html" title="class in hydra.ext.relationalModel">ForeignKey</a></th>
<td class="colLast">
<div class="block">A mapping from certain columns of a source relation to primary key columns of a target relation</div>
</td>
</tr>
<tr class="rowColor">
<th class="colFirst" scope="row"><a href="PrimaryKey.html" title="class in hydra.ext.relationalModel">Primar