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Z39.50 as a Web Service Ralph LeVan Research Scientist.

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Z39.50 as a Web Service Ralph LeVan Research Scientist.

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1 Z39.50 as a Web Service Ralph LeVan Research Scientist

2 Roadmap Why Z39.50 as a Web Service? – The Weaknesses of Classic Z39.50 The Strengths of Classic Z39.50 SRW: Search and Retrieve on the Web SRU: Search and Retrieve with URLs Outlook for SRW/SRU

3 The Weaknesses of Classic Z39.50 Not popular with the Web community – Connection-based Sessions – Binary Encoding – Transmitted directly over TCP/IP Complicated

4 Z39.50 Complicated? 11 Native Services – Init, Search, Present, DeleteResultSet, AccessControl, ResourceControl, TriggerResourceControl, ResourceReport, Scan, Sort, Segment. 7 Extended Services – PersistentResultSet, PersistentQuery, PeriodicQuerySchedule, ItemOrder, DatabaseUpdate, ExportSpecification, ExportInvocation

5 Z39.50 Complicated? 156 page standard – 147 in the 2002 draft Vocabulary from the OSI community – Target, Origin, APDU, A-association, Z-association.. Records described with ASN.1 Attribute Sets

6 The Strengths of Classic Z39.50 Result Sets (a.k.a. Statefulness) Abstraction – Abstract Access Points (Attribute Sets) – Abstract Record Schemas Explain

7 SRW: Search and Retrieve on the Web SOAP (Simple Object Access Protocol) Based – HTTP – XML Records Described in WSDL (Web Service Description Language) 1 Service: SearchAndRetrieve No Documentation :-)

8 Semantically equivalent to classic Z39.50 Gateways Trivial Preserves the experience of the ZIG without the baggage of the standard Syntactic equivalence discounted

9 SRW: The Basics Only one database per request String (not structure) based queries Index Sets, not Attribute Sets One Record Syntax (XML)

10 The SRW Request String Query Integer StartRecord Integer MaximumRecords String RecordSchema

11 The SOAP Encoding of the SRW Request nuclear 4 1

12 The SRW Response String ResultSetReference – ResultSetName – ResultSetTimeToLive Integer TotalHits Records Status (Status Code & Diagnostic)

13 The SOAP Encoding of the SRW Response 115 … 0

14 The SOAP Encoding of the SRW Response 1971 Pions--Scattering. Garland, Richard. Measurement of the charged pion form factor slope at rest. Irvington-on-Hudson, N.Y.,Nevis Laboratories, Columbia University,

15 CQL: Common Query Language Loosely based on CCL Search Boolean & Proximity Operators Index Sets & Indexes Truncation Characters *, # & ? Example: dc.title=harry potter or bib1.isbn= x

16 Explain Now Possible Not practical for classic Z39.50 List of supported Schemas List of supported Indexes

17 SRU: Search and Retrieve with URLs SRW Without the SOAP Wrapper Intended for Thin Clients Example trieveService?query=education&maxRecords=10

18 Outlook for SRW/SRU A solution looking for a problem? Not likely to be quickly adopted by the library community Could show up first in other communities: Geospatial, Biodiversity, OAI(?) Will be seen as a competitor with XML Query

19 Links html html niso ppt niso ppt

20 & Q uestions A A nswers


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