Techniques for processing reference-based SQL/XML operators are provided. Instead of extracting copies of one or more nodes from XML data, a reference-based operator returns a reference to a node. Such a reference is used to determine, for example, whether the corresponding node comes logical before,...http://www.google.com.hk/patents/US7870124?utm_source=gb-gplus-share專利 US7870124 - Rewriting node reference-based XQuery using SQL/SML
