D(node-metadata-equality-string,name:http://www.sleepycat.com/2002/dbxml,=,'users.xml',P(edge-element-equality-string,prefix,user_tuple.userid)) D(node-metadata-equality-string,name:http://www.sleepycat.com/2002/dbxml,=,'users.xml',U) D(node-metadata-equality-string,name:http://www.sleepycat.com/2002/dbxml,=,'items.xml',V(node-element-substring-string,description,substring,'Bicycle')) V(edge-element-equality-string,user_tuple.userid,=,'[to be calculated]') D(node-metadata-equality-string,name:http://www.sleepycat.com/2002/dbxml,=,'bids.xml',n(V(edge-element-equality-string,bid_tuple.itemno,=,'[to be calculated]'),V(edge-element-equality-string,bid_tuple.userid,=,'[to be calculated]'))) P(edge-element-equality-string,prefix,item_tuple.itemno) D(node-metadata-equality-string,name:http://www.sleepycat.com/2002/dbxml,=,'bids.xml',P(edge-element-equality-string,prefix,bid_tuple.itemno)) V(edge-element-equality-string,item_tuple.itemno,=,'[to be calculated]') P(edge-element-equality-string,prefix,bid_tuple.itemno) V(edge-element-equality-string,user_tuple.userid,=,'[to be calculated]') P(edge-element-equality-string,prefix,bid_tuple.userid) P(edge-element-equality-string,prefix,item_tuple.itemno)