CIA 2003 th International Workshop on Cooperative Information Agents CIA th International Workshop on Cooperative Information Agents DIA: Data Integration using Agents Philip Medcraft, Ulrich Schiel, Cláudio Baptista Universidade Federal de Campina Grande Paraíba - Brazil

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:  return before if query has been attended  Dynamic itinerary.  visit all databases of the itinerary  Static 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.