  Nowadays, decisional systems have became a significant research topic in
databases. Data warehouses and data marts are the main elements of such
systems. This paper presents our decisional support system. We present
graphical interfaces which help the administrator to build data warehouses and
data marts. We present a data warehouse building interface based on an
object-oriented conceptual model. This model allows the warehouse data
historisation at three levels: attribute, class and environment. Also, we
present a data mart building interface which allows warehouse data to be
reorganised through a multidimensional object-oriented model.
