AGRIS Multi-Host Search System: Using Dublin Core to homogenise distributed databases Frehiwot Fisseha FAO/WAICENT AGRIS/CARIS and Documentation Unit

Overview * Background - AGRIS * Motivation for AGRIS -MHS * Vision * Challenges * Way forward * Components and arichtecture of the MHS

Background- AGRIS q AGRIS is the international information system for the agricultural science and technology. q AGRIS is a bibliographic database created by FAO in 1974 to facilitate information exchange and to identify world literature dealing with all aspects of agriculture q AGRIS is a co-operative system. 199 national, international and intergovernmental centres participate and submit about records per month q The system collects bibliographic references (to date, about 3 million) to either conventional (journal articles, books) or non-conventional materials (sometimes called "grey literature" e.g. theses, reports, etc.), not available through ordinary commercial channels. q

Motivation for the AGRIS MHS q We have wide range of bibliographic information that should be included into the AGRIS database q Large components of the AGRIS database are existing national bibliographic databases like AGRICOLA and ELFIS. Some of the databases are searchable on the internet and need not be copied or reprocessed by FAO's AGRIS processing group.

Vision q AGRIS as a focal point of access for agricultural information (bibliographic as well as full text) on distributed databases and information systems q uniform presentation of meta information q easily accessible information content

Challenges q Distributed databases q Databases are heterogeneous different data structure different metadata information

Way Forward q Develop a search engine to make a parallel search on distributed databases (Outsource development-ZADI) develop XML wrapper for each co-operating database q Develop common meta elements to homogenise search result set (In-house)

Way forward (Contd.) Related activities q Develop and propose DC based meta data description for agricultural resources for the purpose of resource discovery and interoperability –organise working group to work on proposing DC based standards (agricultural Dublin Core elements and qualifiers) –draft specification for a DC based standard for describing document- like agricultural resources –crosswalk for the existing databases (AGRIS, CARIS, FAO online Catalogue) –posted on Agstandard mailing list for discussion and feed back –work in progress to encode the standard with an XML framework (DTD, RDF)

Client AGRIS-Server Distributed Databases Distributed Databases RequestSearch Result Search Results Requests The AGRIS MHS System

Wrapper Manager Wrapper Manager Transaction Manager Transaction Manager Distributed Databases Distributed Databases Client static pagesdynamic pages AGRIS-WWW-Server Components of the AGRIS MHS

AGRIS-Server Client 1. Login (AGRIS Homepage) and request for the search form (HTTP) 2. Transmission of a static search form (HTML) including intelligent checks (Java-Script) Transaction Manager Transaction Manager AGRIS-WWW-Server static pagesdynamic pages

AGRIS-Server Client 3. Input of search criteria including the searchable databases and request sending (http) AGRIS-WWW-Server static pagesdynamic pages Transaction Manager Transaction Manager 4. Request transmission to dynamically generate the search result page

AGRIS-Server Transaction Manager Transaction Manager Wrapper Manager Wrapper Manager 5. Kernel activation and request transmission including request syntax and search criteria (databases, fields, search pattern) Distributed Databases Distributed Databases 6. Distributed requests on distributed databases through IP (XML) 7. Search result delivery (XML) 8. Compilation of one homogenous result set and delivery Using AG-DC

AGRIS-Server Transaction Manager Transaction Manager Client 9. Result set conversion (XML->HTML) and transmission 10. Request answering (HTML) AGRIS-WWW-Server static pagesdynamic pages Search Result in AG-DC format

Wrapper Manager Wrapper Manager Transaction Manager Transaction Manager Distributed Databases Distributed Databases Client AGRIS-Server AGRIS-WWW-Server static pagesdynamic pages

AGRIS-Kernel XML Query Generator XML Result Set Composer XML Result Set Composer 8. Compilation and Transmission of one homogen result set Transaction Manager Transaction Manager Distributed Databases Distributed Databases Knowledge Base (Database - URL) Knowledge Base (Database - URL) 6. Translation of the http request into a standardised XML query and delivery to the databases 7. Search result delivery (XML) 5. Kernel activation and request transmission including request syntax and search criteria (databases, fields, search pattern)

Client AGRIS-Server Distributed Databases Distributed Databases Request Search Result Request

AGRIS-Server XML-Wrapper Distributed Databases Distributed Databases Database-Kernel Data, Indexes Knowledge Base AGRIS-XML local Schemes 6.1. Translation of the XML- Request into the database specific syntax, opening of a retrieval session and activation of the database kernel 6.2. Database search 6. Translation of the http request into a standardised XML query and delivery to the databases 7. Search result delivery (XML) With AG-DC elements

AGRIS-Server Distributed Databases Distributed Databases 6.3. Search result in database specific syntax 6.4. Conversion into XML 6. Translation of the http request into a standardised XML query and delivery to the databases 7. Search result delivery (XML) XML-Wrapper Database-Kernel Data, Indexes Knowledge Base AGRIS-XML local Schemes

Client AGRIS-Server Distributed Databases Distributed Databases Request Search Result Request

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