D(node-metadata-equality-string,name:http://www.sleepycat.com/2002/dbxml,=,'books.xml',u(P(edge-element-equality-string,prefix,chapter.title),P(edge-element-equality-string,prefix,section.title))) u(P(edge-element-equality-string,prefix,section.title),P(edge-element-equality-string,prefix,chapter.title))