An a Priori Approach for Automatic Integration of Heterogeneous and Autonomous Databases

Abstract

Data integration is the process that gives users access to multiple data sources though queries against a global schema. Semantic heterogeneity has been identified as the most important and toughest problem when integrating various data sources. Several approaches were proposed to deal with this problem. These approaches can be classified using three criteria: (1) data representation which means whether data of sources will be materialized in a warehouse at the integrated system level or accessed via a mediator, (2) the sense of the mapping between global and local schemas (e.g., Global as View, Local as View) and (3) the nature of the mapping (manual, semi automatic and automatic). Mapping is manual each time when ontologies are not used to make explicit data meaning. It is semi automatic when ontology and ontology mapping are defined at integration level. In this paper, we propose a fully automatic integration process based on ontologies. It supposes that each data source contains a conceptual ontology that references a shared ontology. The mappings between a local ontology and the shared ontology is defined at database design time and also embedded in each source. This approach is implemented using PLIB-based ontologies (officially ISO 13584). It is assumed that there exists a domain ontology, but each data source may extend it by adding new concepts and properties. Therefore the shared ontology is referenced when ever it is possible. This integration approach was developed for automatic integration of component databases. It is currently prototyped in various environments including OODB, ORDB, and RDB.

A Framework for Fuzzy Ontology Storing onto Relational Database within an a Priori Data Integration System

“…Heterogeneity, which can characterize data sources used in data integration systems such as mediators or data warehouses, may be of different kinds: syntactic, systematic, schematic or structural. Actually, in classification of data integration systems with respect to automaticity criterion in [5], we conclude that automaticity can be strongly achieved when using ontology in an a priori approach then in a posteriori approach [6]. The latter means ontology is considered once the data sources have been set up.…”

Domain Ontologies: A Database-Oriented Analysis

“…When domain ontoogies are explicitly represented in databases, the integration may be fully automated even when each source specializes locally the shared ontology (Bellatreche et al, 2004). In the Semantic Web approaches, the link between source and ontology is usually supported by metadata.…”

OntoAPI: An Ontology-based Data Integration Approach by an a Priori Articulation of Ontologies

“…In this work, we first propose a semantic integration approach by articulating ontologies [2], called OntoAPI to solve the problem of source autonomy, by allowing to each source (or peer) participating in the integration process to define its own ontology that references a shared ontology. Secondly, we propose a model dealing with the problem of management of asynchronous evolution of ontologies and data.…”

“…There is an important number of research projects dealing with data integration problem. The spectrum ranges from early multi-database systems [1] over data warehouse systems [2], mediator systems [3], [4], to peer to peer systems [5], [6], [7]. Note that each integration system shall take into consideration the two following aspects: (1) the procedure of resolving various conflits (naming, scaling, confounding and representation conflicts) from multiple sources due to semantic and syntaxic heterogeneities.…”

“…Ontologies are then used to describe the semantic of sources and to make their contents more explicit. (2) The second aspect represents the source autonomy, known as the receiver heterogeneity problem [9] meaning that sources are not forced to adapt their data and semantics for the integration system [9] (i.e., most of the sources operate autonomously). They are free to modify their structures, remove some data without any prior "public" notification.…”