Résumé: Missing information, imprecision, inconsistency, vagueness, uncertainty, and ignorance abound in information systems. Such imperfection is a fact of life in database systems. Although these problems are widely studied in relational database systems, this is not the case in conceptual query systems. And yet, concept-based query languages have been proposed and some are already commercial products. It is therefore imperative to study these problems in concept-based query languages, with a view to prescribing formal approaches to dealing with the problems. In this article, we have done just that for a concept-based natural language query system that we developed. A methodology for handling and resolving each type of imperfection is developed. The proposed approaches are automated as much as possible, with the user mainly serving an assistive function.

Langue: Anglais