In recent years, the use of NoSQL systems to store and exploit massive databases has been steadily increasing. These systems provide a great flexibility of use thanks to their "schema less" property. However, the schema of the NoSQL DB is necessary to allow users (especially decision-makers) to express their queries. In what follows, the notion of "NoSQL DB" is used to designate a DB managed by a NoSQL DBMS. The purpose of this article is to extract the schema from a document-oriented NoSQL DB. For this, we propose an incremental development process of the schema during the exploitation of the Database