[seek-dev] implement XQuery in EcoGrid and SRB

Bing Zhu bzhu at sdsc.edu
Thu Jun 5 17:41:45 PDT 2003

Peter and Jing,

The whole EcoGrid data stored in metacat, SRB, (others), can be viewed as a
virtual XML document (or a DOM object). This DOM object has at least two
metacat and srb.

Since SRB is organized in collection and sub-collection hierarchical
architecture, each collection is a subnode in the XML tree under
(/EcogGrid)/srb. (Actually
we can define a XML schema for our EcoGrid data. ). Thus we can implement
XQueries in
our EcoGrid to act as a common query engine across different systems
(metacat, SRB, etc.)

I compiled some examples of XQueries to search documents in SRB.

(1)	Search all design documents stored in SRB collection,
      which were created before Sept 23, 2002.

            for $e in document(“EcoGrid.xml”)/srb/home/bzhu.sdsc/designDocs
            where $e/@objtype = “file” and $e/@time lt date(“09-23-2002”)
            return <datasrc>SRB</datasrc><dataname>$e/@name</dataname>

(2)	find all datasets stored in SRB which  have titles containing “protein”
      are owned by Professor John whose user name is john.

            for $e document(“EcoGrid.xml”)/srb/home//
            where $e/@objtype = “file” and
                  contains($e/@name like, “protein”) and
                  contains($e/@owner, “john”)
            return <datasrc>SRB</datasrc><dataname>$e/@name</dataname>

Jing, Would you provide some examples (or info) regarding searching in

And We also can start with designing a XML schema for whole EcoGrid data
based on following (roughly).


        collection (attribute: objtype, time, owner, 
             dataset (attribute: objtype, time, owner, size, container,
                  user-defined metadata
     other data source


Bing Zhu
San Diego Supercomputer Center
bzhu at sdsc.edu

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