For a same domain, several DataBases (DBs) exist. The emergence of classical web to the semantic web has contributed to the appearance of the notion of ontology that have shared and consensual vocabulary. For a given, it is more interesting to take advantage of existing databases, to build an ontology. Most of the data are already stored in these databases. So many DBs can be integrated to enable reuse of existing data for the semantic web. Even for existing ontologies, the relevance of the information they contain requires regular updating.