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It’s Distributed searching, Jim

It’s Distributed searching, Jim. But not as you know it! ZIG meeting, Leuven July 12th, 2000 Bert Degenhart Drenth ADLIB Information Systems BV bert@nl.adlibsoft.com http://www.nl.adlibsoft.com. A problem to be solved. Multiple database architectures (ODBC, ADO, other)

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It’s Distributed searching, Jim

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  1. It’s Distributed searching, Jim But not as you know it! ZIG meeting, Leuven July 12th, 2000 Bert Degenhart Drenth ADLIB Information Systems BV bert@nl.adlibsoft.com http://www.nl.adlibsoft.com

  2. A problem to be solved Multiple database architectures (ODBC, ADO, other) Use of standard components Use of standard protocols Distributed database Close to Web development Use for ‘cross domain’ application: library, museum and archives.

  3. An alternative architecture 3 functions • Query through URL’s (get/post method) • Return results in XML • Use a broker or gateway to combine results

  4. A prototype: 2 databases: an ODBC source (MS-Access)an ADLIB database ODBC source contains simple ‘library’ records ADLIB database contains Dublin Core records

  5. System setup: Web browser url HTML ASP broker url XML XML url translator translator SQL AQL records TDS ADLIBdatabase ODBC source

  6. Technology used 1. Express query in URL (proprietary syntax) 2. Query is handed to translators by a HTTP request using Microsoft.XMLHTTP 3. Translators hand query to database engine using ODBC (ACCESS) or native calls 4. Translators return XML to broker 5. Broker uses XMLDOM to integrate results 6. Broker runs on ASP written in Jscript

  7. Comparison with Z39.50 Differences: No BER No ‘library specific’ technology Current implementation does not split between search and retrieve No extended services

  8. Comparison with Z39.50 Similarities Asynchronous searches possible For ‘real’ applications standardisation needs to take place on: Definition of query URL’s The three S-s : Syntax, Structure and Semantics Syntax : XML Structure : return elements (DTD/schema) Semantics : attribute set and profile The mechanism for setting up this can be ‘borrowed’ from Z39.50

  9. Decouple transport mechanism from application Technology changes and is driven by forces outside of the library / museum / archive arena If you can’t beat them, join them Inertia (MARC is still there!)

  10. Developments in CIMI : what happened after the Z39.50 testbed • Testbed proved that the technology worked, but no practical implementations are out there! • No support for Z39.50 in commercial products

  11. Developments in CIMI : what happened after the Z39.50 testbed • After the Z39.50 testbed the Dublin Core testbed was conducted. • Proved to be successful, with a central repository. • Support for DC in XML in commercial products.

  12. Developments in CIMI : what happened after the Z39.50 testbed… • CIMI moved from DC to intra community data exchange, based on XML. • MDA and CIMI are producing a DTD for Spectrum, scheduled for november 2000 • The CIMI Z39.50 profile could be used as a basis for distributed applications using HTTP technology, notably important:record schema (dtd / XML-schema)access points and semantics

  13. The end for Z39.50? My personal opinion : NO! Emphasis has to shift from ‘bits on the wire’ to the Three S-es for a variety of information services Integration, communication needs to take place with similar fields : TEI, EAD, Spectrum-XML and DC Of course: existing systems need upgrade / maintenance

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