Abstract. The World Wide Web infrastructure together with its more than 2 billion users enables to store information at a rate that has never been achieved before. This is mainly due to the will of storing almost all end-user interactions performed on some web applications. In order to reply to scalability and availability constraints, many web companies involved in this process recently started to design their own data management systems. Many of them are referred to as NOSQL databases, standing for 'Not only SQL'. With their wide adoption emerges new needs and data integration is one of them. In this paper, we consider that an ontology-based representation of the information stored in a set of NOSQL sources is highly needed. The main motivation of this approach is the ability to reason on elements of the ontology and to retrieve information in an efficient and distributed manner. Our contributions are the following: (1) we analyze a set of schemaless NOSQL databases to generate local ontologies, (2) we generate a global ontology based on the discovery of correspondences between the local ontologies and finally (3) we propose a query translation solution from SPARQL to query languages of the sources. We are currently implementing our data integration solution on two popular NOSQL databases: MongoDB as a document database and Cassandra as a column family store.
Regarding the semantic web data source which represents the subject of this paper, all approaches proposed in order to bridge the gap between this latter and NoSQL database (MongoDB) are interested much more to the mapping direction of semantic web to MongoDB; we quote for instance: the paper REF that proposes a query translation solution from SPARQL to query languages of the NoSQL sources considered in this work (MongoDB as a document database and Cassandra as a column family store).
Ontology Based Data Integration Over Document and Column Family Oriented NOSQL
ArXiv
ArXiv
Computer Science