public function addReference( PgAttribute $primaryKey, $includeChildTables = true )
    {

        $this->references->add( $primaryKey );
        $primaryKey->isReferencedBy->add( $this );

        if( $includeChildTables || true ) {
            foreach( $primaryKey->getRelation()->getChildren() as $child ) {
                $this->addReference($child->getAttributeByName($primaryKey->name), true);
            }
        }

        return;

        // TODO. Add support for inheritance
        $query = new Query(
            "SELECT oid::text || '.' || %attnum:int%::text FROM dev.relationDescendants( %oid:int%::oid ) as _ ( oid );",
            array(
                'attnum' => $pk->get('attnum'),
                'oid' => $pk->get('relation')->get('oid')
            )
        );

    }