22. The method of claim 1 wherein: the entry for a given node includes hierarchical data that indicates a hierarchical position of the given node within the XML document that contains the given node; and the method further comprises building a secondary index for accessing entries in said index based on said hierarchical data.
22. The method of claim 1 wherein: the entry for a given node includes hierarchical data that indicates a hierarchical position of the given node within the XML document that contains the given node; and the method further comprises building a secondary index for accessing entries in said index based on said hierarchical data. 23. A computer-readable storage medium storing one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 22 .