In this paper, we propose a semantic approach for automatic ontology learning from heterogeneous relational databases in order to facilitate their integration. The semantic enrichment of heterogeneous databases, which cover the same domain, is essential to integrate them. Our approach is based on Wordnet and Wup's measure for measuring the semantic similarity between elements of these databases. It is described by a detailed process that can allow not only the generation of ontology but also its evolution as the evolution of its databases. We applied our approach in the alimentation risks field that is characterized by a large number of scientific databases. The developed prototype has been compared with similar tools of generation ontology from databases. The result confirms the quality of our prototype that returns the generic ontology from many relational databases.
The integration of incomplete and uncertain information has emerged as a crucial issue in many application domains, including data warehousing, data mining, data analysis, and artificial intelligence. This paper proposes a novel approach of mediation-based integration for integrating these types of information from heterogeneous relational databases. We present in detail the different processes in the layered architecture of the proposed flexible mediator system. The integration process of our mediator is based on the use of fuzzy logic and semantic similarity measures for more effective integration of incomplete and uncertain information. We also define fuzzy views over the mediator’s global fuzzy schema to express incomplete and uncertain databases and specify the mappings between this global schema and these sources. Moreover, our approach provides intelligent data integration, enabling efficient generation of cooperative answers from similar ones, retrieved by queried flexible wrappers. These answers contain information that is more detailed and complete than the information contained in the initial answers. A thorough experiment verifies our approach improves the performance of data integration under various configurations.
The object-relational databases (ORDB) are powerful for managing complex data, but they suffer from problems of scalability and managing large-scale data. Therefore, the importance of the migration of ORDB to NoSQL derives from the fact that the large volume of data can be handled in the best way with high scalability and availability. This paper reports our metadata-driven approach for the migration of the ORDB to document-oriented NoSQL database. Our data migration approach involves three major stages: a preprocessing stage, to extract the data and the schema's components, a processing stage, to provide the data transformation, and a post-processing stage, to store the migrated data as BSON documents. The approach maintains the benefits of Oracle ORDB in NoSQL MongoDB by supporting integrity constraint checking. To validate our approach, we developed OR2DOD (Object Relational to Document-Oriented Databases) system, and the experimental results confirm the effectiveness of our proposal.
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