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DIA: Data Integration using Agents Philip Medcraft, Ulrich Schiel, Cláudio Baptista Universidade Federal de Campina Grande Paraíba - Bra z il. CIA 2003 7 th International Workshop on Cooperative Information Agents. Introduction.
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DIA: Data Integration using Agents Philip Medcraft, Ulrich Schiel, Cláudio Baptista Universidade Federal de Campina Grande Paraíba - Brazil CIA 20037th International Workshop on Cooperative Information Agents
Introduction • Web new requirements for data integration. • The Semantic Web ontologies to solve the semantic heterogeneity. • Federated Database Ontology. • Ontologies & software agents data integration
Introduction - DIA • A solution for semantic integration of data in a federated database, • using mobile agents and ontologies. • Solve the following problems: • Unnecessary access to all data sources; • Excessive data flow.
Introduction • An ontology defines the concepts and relationships between concepts of a particular domain. • Ontology the global schema of a federation of DBs. • Rules Global-Local Schema mapping
Mobile Agents • Some benefits: • Reduce network traffic; • Execute autonomously; • Adapt dynamically; • Plattform independent.
Design Patterns • Mobile agent patterns. • Itinerary pattern (modified). • Master-slave pattern.
DIA DIA Architecture
DIA – Preparing the mobile agent itinerary • The Master-agent knows the schemas of the federated databases. • Given a global query select the host whose schema attend the query (Selected itinerary)
DIA – Preparing the mobile agent itinerary • Given the following query: SELECT Cod, SUM(Credits) FROM Customer WHERE Cod = “02757” • A database whose schema does not contain a corresponding attribute to the “Credits” element, cannot attend the query.
DIA – Improving the Itinerary Pattern • Categories of queries: • visit all databases of the itinerary Static itinerary; • return before if query has been attended Dynamic itinerary.
DIA – Improving the Itinerary Pattern • Ex 1: “Give me the clients whose salaries are above 1,000”. STATIC • Ex 2: “Is the salary of “Philip” above 1,000?”. DYNAMIC • Ex 3: “Give me the sum of the salaries of clients whose credit limits are above 1,000”. STATIC • Ex 4: “Give me the name of a client where the sum debits is superior to 10,000”. DYNAMIC
DIA – Example SELECT CPF, NAME, SUM(Credits) FROM Customer GROUP BY CPF
DIA – Local Integration • Concatenation • Integration (by an aggregate function)
DIA – Local Integration Result example in XML syntax
DIA Integrating two XML results
DIA – The federated system interface The interface
DIA – Implementation and test • Java + JDBC • JXML (DAML-OIL graphical representation) • Grasshopper • TEST with a federation of 3 DBMS:Oracle + Interbase + SQL Server
Conclusion • Distributed corporations have a group of well known databases which maintain: • The knowledge of the stored information; • The stability of the federation members.
Conclusion • Ontology: • Global Schema; • Rules for mapping to local schemas • Mobile agents: • Reduce information flow; • Adequately choose the data sources to be consulted.