CNI, 4th April 2006 Slide 1 Key Standards Update: SRU (“Technical” Details) Dr. Robert Sanderson...
-
Upload
valerie-richard -
Category
Documents
-
view
215 -
download
3
Transcript of CNI, 4th April 2006 Slide 1 Key Standards Update: SRU (“Technical” Details) Dr. Robert Sanderson...
CNI, 4th April 2006 Slide 1
Key Standards Update:Key Standards Update:SRU (“Technical” Details)SRU (“Technical” Details)
Dr. Robert SandersonDept. of Computer ScienceUniversity of Liverpool
http://www.csc.liv.ac.uk/~azaroth/http://www.loc.gov/standards/sru/http://srw.cheshire3.org/
CNI, 4th April 2006 Slide 2
OverviewOverview
Aims and Motivations
Other Protocols: OAI, OpenSearch
Response Format Additions
Sort
Proximity
Extensions, Diagnostics
CNI, 4th April 2006 Slide 3
OverviewOverview
Overall aims/goals for the changes towards SRU 1.2
Reduce protocol complexity without losing important
features
Allow easier/deeper integration with other protocols
Correct past mistakes (mea culpa!)
Improve visibility, understanding and implementations
Escape the “library ghetto”
... Profit!
CNI, 4th April 2006 Slide 4
Ease of IntegrationEase of Integration
Other protocols to interoperate with:
Open Archives Initiative (OAI-PMH)
OpenSearch
OpenURL
“Web 2.0” / “Library 2.0” enabling techniques
(Should change name to “OpenSRU 2.0” ??)
CNI, 4th April 2006 Slide 5
Ease of Integration: OAIEase of Integration: OAI
Formalize a profile to allow OAI to be implemented over
SRU
rec.identifier Search by
identifier
rec.lastModificationDate Search by
modification time
rec.collectionIdentifier Search by 'set'
Plus extension to allow OAI header information to be
returned
(record is in which sets, etc)
CNI, 4th April 2006 Slide 6
Ease of Integration: Ease of Integration: OpenSearchOpenSearch
SRU compatible profile of OpenSearch
OpenSearch allows the server to pick the names of
parameters ... Pick names that match SRU's
parameters
Allow query extensions to build CQL from OpenSearch's
parameters.
x-dc-title=Lord of the Rings&x-dc-creator=Tolkien
Unaware SRU and OS servers will just ignore.
CNI, 4th April 2006 Slide 7
Response Format Response Format AdditionsAdditions
Allow record Identifier (metadata level) to be returned in the
record structure
Allow the full base URL to be returned in the response
(within echoedRequest)
<record> <recordSchema>info:srw/schema/1/dc-v1.1</recordSchema> <recordPacking>xml</recordPacking> <recordIdentifier>info:pmid/15411833</recordIdentifier> <recordData> ... </recordData></record>
<echoedRequest> <baseUrl>http://srw.cheshire3.org/services/spy</baseUrl> <version>1.2</version> ...</echoedRequest>
CNI, 4th April 2006 Slide 8
SortSort
Sort has been a bugbear since version 1.0
Extend CQL to include sorting specification
Allow use of indexes with modifiers to specify
semantics
(Previously XPath expressions)
CQL parsers can be used to parse both, reducing
workload
(assuming that an existing CQL parser is used)
Enhances independence of CQL as query language
Example: dc.title any fish sortBy dc.date/ascending
dc.creator
CNI, 4th April 2006 Slide 9
ProximityProximity
One of the most complicated parts of SRU/CQL
No easy solution, but some improvements...
Recommendations for how to extend proximity
modifiers
-- Use a new context set for modifiers
Explainable server defaults for proximity modifiers
Improved documentation
Agreement to not agree on anything further until the
OASIS
Technical Committee to include other interested
parties
CNI, 4th April 2006 Slide 10
Extensions, DiagnosticsExtensions, Diagnostics
Issue: Number of matching records may be unknown or
approximate, no way to notify this condition
New diagnostics:
Number of records approximate
Number of records truncated
Request Extension:
Approximate record count is acceptable
CNI, 4th April 2006 Slide 11
Extra Term InformationExtra Term Information
Issue: Desirable to return sub-query level detailsEg: How many records matched in one part of the
query
Details to return need to be extensible
Solution: Add extraTermInfo into the XCQL
representation to be returned in the response
Some general extensions will be defined, but allows
implementors to include any information they think
appropriate
Needs a parameter to request that the details be
returned
(like all SRU extensions)
CNI, 4th April 2006 Slide 12
Thank you!Thank you!
Questions?