Let's say I have a database built from 40+ XML documents, each with about 4 million nodes for a total of about 404 million nodes, of which 30k are high-level records of interest. Let's say that a given node of interest (a PubMed record, actually) may occur once in this database for each time it has been updated, and I can identify the most recent version of that record by the PubMed ID and the filename (an ascending sort of the filenames sorts them from least recent to most recent).

Is there a way in XQuery I can identify a record in this database not only by its PubMed ID but also limit the result set by source document name? I know that `db:path($elem)` gives me the document name for an element, but I want to use the document name to help pick out the element from among several that may share its PMID.

Context: I have 26 such databases, each of which contains 43-44 source files, each of which contains 30000 records. I have built one index database that, for each record, includes PubMed ID, source filename, and database name. For a given PMID I can very quickly retrieve the db name and the file name, but I need to search the db not only by PMID but also by source filename in order to select the most recent version of a record.

Thank you & all the best,

Chuck Bearden