Conceptual data model with structured objects for statistical databases

We present a conceptual data model, called SDM, which is able to represent the relationships between elementary and statistical data at a conceptual level. SDM borrows elements from research both in object oriented databases and in knowledge representation. In addition it has suitable mechanisms to form classes of individuals by classifying the instances of a target class according to some specified criteria. Notably, the class resulting from such a statistical aggregation can then be treated exactly as a class of elementary data. This ability fulfils the often perceived necessity, in modeling real domains, of treating statistical aggregates and elementary data in an homogeneous way.