Systems that filter information from one or more data sources that are usually accessed using wrappers. The main goal of these systems is to allow users to make complex queries over heterogeneous sources as if it were a single one, using an integration schema. Mediators offer user interfaces for querying the system based on the integration schema. They transform user queries into a set of subqueries that other software components (the wrappers), which encapsulate data sources’ capabilities, will solve.
Published in Chapter:
Data Integration: Introducing Semantics
Ismael Navas-Delgado (University of Málaga, Spain) and Jose F. Aldana-Montes (University of Málaga, Spain)
Copyright: © 2009
|Pages: 11
DOI: 10.4018/978-1-60566-242-8.ch050
Abstract
The growth of the Internet has simplified data access, which has involved an increment in the creation of new data sources. Despite this increment, in most cases, these large data repositories are accessed manually. This problem is aggravated by the heterogeneous nature and extreme volatility of the information on the Web. This heterogeneity includes three types: intentional (differences in the contents), semantic (differences in the interpretation), and schematic (data types, labeling, structures, etc.). Thus, the increase of the available information and the complexity of dealing with this amount of information have involved a considerable amount of research into the subject of heterogeneous data integration. The database community, one of the most important groups dealing with data heterogeneity and dispersion, has provided a wide range of solutions to this problem. However, this issue has also been addressed and solutions have been offered by the information retrieval and knowledge representation communities, making this area a connection point between the three communities.