Date Added: Oct 2009
Although deductive databases are based on a well established formalism, they didn't know the expected success. Their use was limited to the academic purpose. Indeed, the deductive database management systems are judged abstract, rare in commercial offers, and often expensive. In among the abstract concepts of the deductive databases, the authors mention the case of the negation and its treatment by the stratification. In this paper, they propose a convivial approach that aims to make transparent theses concepts relatively abstracted and to permit a friendly use of deductive databases and stratified database.