Mapping Relational Databases to Ontologies: n Approach Combining Semantic Enrichment nd Mapping Consistency
Date Issued
2008
Date
2008
Author(s)
Liu, Jun-Hong
Abstract
One of the core challenges of the Semantic Web is to transform mass existing information to OWL ontologies. This mass existing information is mainly composed of the contents on the Web. Therefore, to realize the Semantic Web, it will be necessary to map the Web contents to OWL ontologies. Manually mapping the Web contents to OWL ontologies is impractical since the Web has well over billions of Web pages and most of the contents of Web pages is stored in the relational databases and hence hard to be found by search engines (so-called the ``emph{deep Web}"). Hence, to make these contents available for the Semantic Web, an effective way is to map the relational databases underlying the deep Web to domain-related OWL ontologies. In this thesis, we propose a semi-automatic approach for directly mapping relational databases to OWL ontologies. This approach takes the concept of cluster analysis in data mining to find the matching classes group (MCG) for every table, where every found class of MCG will satisfy the mapping consistency stating that the mapping results should not violate the fact expressed in the relational database. We divide our approach into two phases. The first phase primarily uses the semantic information to map the foreign keys of a relational database to object properties of OWL ontologies to get the features of MCGs for tables. Different from other approaches, we not only take into consideration the Generalization/Specialization relationship between tables but also take advantage of the inverse relationship between tables which are implicitly expressed in a relational database to construct an implicit matching level between foreigns keys and object properties. The second phase uses the mapping results of the foreign keys as clues of features to find MCGs for some tables and then takes the MCGs of these tables to find MCGs for other tables. Finally, every table is mapped to its MCG. A prototype system demonstrates that our approach performs well on several domain samples from the real world.
Subjects
Semantic Web
OWL
Deep Web
Mapping
Relational Databases
Cluster Analysis
Mapping Consistency
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