OntoBase's goal is to make lightweight conceptual data access possible. "Lightweight" refers to the effort required in order to perform simple operations with data. "Conceptual" refers to the level of abstraction at which the data can be handled without detailed knowledge of its source. OntoBase achieves this goal by employing a formal conceptual model called "ontology" that mediates all access to data. Creating and using ontology typically requires a substantial up-front effort. OntoBase reduces the effort by reverse-engineering initial ontology from the database schema.