[seek-dev] implement XQuery in EcoGrid and SRB

[Bing Zhu]

Dave,

I am not clear about the other systems such as metacat. It is my intent of
my mail
to give my suggestion using SRB as an example and would like to know other
systems.

A typical example of using SRB as a datagrid to model data and store is that
users usually
build collections and then upload their files such as images into
collections. And then
researchers or scientists can use SRB's metadata functions to add
descriptive metadata
for those files. After re-investigating the SRB framework for implementing
XQuery, I found
that it is possible to use a schema to describe SRB data model as I
described in my
previous mail. If a team maps their XML schema into SRB data model and store
data in SRB,
this approach of using XQuery is still suitable to be used as a search
engine.

Bing




-----Original Message-----
From: Dave Vieglais [mailto:vieglais at ku.edu]
Sent: Thursday, June 05, 2003 8:46 PM
To: bzhu at sdsc.edu
Cc: peter.mccartney at asu.edu; tao at nceas.ucsb.edu; jones at nceas.ucsb.edu; Arcot
Rajasekar; seek-dev at ecoinformatics.org
Subject: Re: [seek-dev] implement XQuery in EcoGrid and SRB


Hi Bing,

Your argument and examples below assume that all data sources
contributing to the ecogrid shall conform to a common schema, which
seems overly restrictive even though it does make building XQuery
statements a bit easier since you are then working with a single schema.

I'm not sure that this is the intent of the ecogrid implementation, but
please correct me if I'm mistaken.

regards,
   Dave V.


Bing Zhu wrote:
> 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
> sub-nodes,
> 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,
> /home/bzhu.sdsc/designDocs,
>       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”
> and
>       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
> metacat?
>
> And We also can start with designing a XML schema for whole EcoGrid data
> model
> based on following (roughly).
>
> EcoGrid
>      Metacat
>           …
>      SRB
>         collection (attribute: objtype, time, owner, …)
>              dataset (attribute: objtype, time, owner, size, container,
> resource, …)
>                   user-defined metadata
>      other data source
>
>
> Cheers,
> Bing
>
> =====================================================
> Bing Zhu
> San Diego Supercomputer Center
> bzhu at sdsc.edu
> (858)534-8373
> =====================================================
>
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