integrating bibliographical data from heterogeneous digital libraries eike schallehn, martin endig,...

Integrating Bibliographical Data from Heterogeneous Digital Libraries

Eike Schallehn, Martin Endig, Kai-Uwe Sattler

Otto-von-Guericke-University MagdeburgInstitute for Technical and Business Information SystemsPO Box 412039016 MagdeburgGermany

ADBIS - DASFAA 2000 SYMPOSIUM

September 5 - 8, 2000


Eike Schallehn Martin Endig

Kai-Uwe Sattler

2ADBIS - DASFAA 2000 SYMPOSIUM

Overview

• Introduction• Specific requirements• General overview of the approach• Source descriptions• XML adapter• Special application: Citation Linking• Conclusion and outlook



Kai-Uwe Sattler


Introduction

• Integration of bibliographical metadata:author, title, publisher, citations, ...

• Wide range of existing providers– Specific for research or geographical area– Publishers, libraries, resellers– differ in scope, quality and quantity of maintained data

• Problems for users– Knowledge about locality, scope, quality etc. is required

• Goal: single point of access



Kai-Uwe Sattler


General Overview (1)

FederationLayer

Adapter/SourceLayer

...

AdapterAdapterAdapterAdapter

Higher-level services

Single Point of Access

Federation Service

DBLP

ApplicationLayer

Publisher:

Springer

Publisher:

Spektrum

DBN



Kai-Uwe Sattler


General Overview (2)

• non-cooperative providers:– WWW databases– Z39.50 sources

• cooperative providers:– Databases (Relational, O-R, etc.)– sources with limited query facilities

capable of providing XML

Adapters for certain classes of providers



Kai-Uwe Sattler


Special Requirements (1)

• Efficient acces for global applications:– Object-relational conforming to standards– flexible import and integration regarding great

numbers of constantly changing systems

• Minimal provider-side resource consumption:– limited query facilities often exist– additional functionality constrained by local

resources

Assumption: common interest in cooperation (on a certain level)



Kai-Uwe Sattler


Special Requirements (2)

• Efficient transfer:– usage of XML as transfer standard– size of intermediate results critical factor for

possibly slow network connection– move queries with high selectivity to the source

• Minimal provider-side implementation efforts: – only wrapping of existing functionality required– tools for design based on source description– XML can easily be created



Kai-Uwe Sattler


Source Description (1)

• Access to local sources mainly depends on their query capabilities

• Global query re-writing and query processing based on these information

• Example: WWW-databases– Constant selections – Set of allowed comparison operators per attribute– simple combinations

Corresponding description required



Kai-Uwe Sattler



• Example: Source1 exports a relation BookStore and allows equality match for author and title, and either separate usage or a simple combination

alter table BookStore set query contraints ( predicates ((authors,=),(title,=)), combinations((author),(title),(author,title)));

• Example continued: Source2 exports a relation Books and allows only equality match on title



Kai-Uwe Sattler



ÓDBMS´´Saake´

titleauthors

´Heueráuthors

´Heueráuthors ´Saakeáuthors

ÓDBMS´title

(BookStore) (BookStore) (Books) (Books)

select * from Publications

where title=ÓDBMS´ and authors=´Saake´ or authors=´Heuer´;



Kai-Uwe Sattler


XML Adapter (1)

• XML for transfer of bibliographical metadata– Cooperative providers– Provider-specific DTD– Underlying data management may vary

Transformation to object-relational structures• Application of XSLT

– Intermediate step: Transformation to internal DOM representation according to own DTD

– Design of XSLT mapping supported by tools

• Further result and query processing at federation layer



Kai-Uwe Sattler


XML Adapter (2)

select *

from Publications

where title like ´ODBMS´;

<ROWSET>

<ROW num=„1“>

<ID>1</ID>

<TITLE>ODBMS</TITLE>

<AUTHORS>Heuer, A.</AUTHORS>

</ROW>

...

</ROWSET>

Example Query: Possible XML Result:



Kai-Uwe Sattler


XML Adapter (3)

Source

Description

XSLT

FRAQL Query Processor

XML

Query Evaluator

...

Query Translator

XML Parser

Result Translator

...

...

...



Kai-Uwe Sattler


Application: Citation Linking

A d a9 8A d a9 8S co 9 8

D a tab asesD a tab asesD ig . L ib ra rie s

A d am sA d am sS co tt

S co 9 8M e y 9 2M o o 9 4

K ey Title A u tho rs R eferences

M o o 9 4……

S Q L……

M o o re……

………

K ey Title A u tho rs R eferences

M o o 9 4M e y 9 2

M o o 9 4M e y 9 2 a

P u b l_ 2P u b l_ 3

key id sou rce

A d a9 8S co 9 8

P u b l_ 1P u b l_ 1

D a tab asesD ig . L ib ra rie s

A d am sS co tt

id sou rce title au tho rs

M o o 9 4 P u b l_ 2 S Q L M o o re

id sou rce title au tho rsS co 9 8M e y 9 2 aM o o 9 4

id sou rce re f_ id re f_ source

A d a9 8A d a9 8S co 9 8

P u b l_ 1P u b l_ 1P u b l_ 1

P u b l_ 1P u b l_ 3P u b l_ 2

Local re lation src1.Publ Local re lation src2.Publ

M apping tableM apPubl

Im port re lation Publ_1Im port re lation R ef_1

Im port re lation Publ_2

Integrating citation information from various sources:



Kai-Uwe Sattler


Conclusion and Outlook

• Application of concepts known from the area of federated and mediator-based systems

• Focus on adapter for partially cooperative providers of bibliographical data– Description of query capabilities for efficient distributed

query processing– Result transfer based on XML– Result transformation based on XSLT

• Better tool support• Improve identification of same-objects

integrating bibliographical data from heterogeneous digital libraries eike schallehn, martin endig,...

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