International Journal of Information Studies Fayech Ines, Ounalli Habib 4 1 2000 https://www.dline.info/ijis/fulltext/v4n1/ijisv4n1_3.pdf In this paper, we are interested in the use of domain ontologies as a semantic enrichment for traditional databases. Particularly, we address the problem of semantically querying a single database using domain ontology. Our first aim is to help the user in his search when his initial query doesn’t return any result. So, we propose an approach allowing the user to express his interrogation in a relatively free way. It is an ontological approach for SQL query expansion generating a set of queries. The proposed approach is based on a domain ontology constructed from the database schema. It is a semantic model for the considered database schema.