What are main differences between FDM and CoM?
• For both COM and FDM the goal is to achieve a naturalness of data representation and manipulation. • Both models rely on the notion of derived properties. • Both models have rather similar query languages. • The mechanism of function inversion in FDM is analogous to the mechanism of inverse dimensions in COM. • FDM does not constraint a structure of functions and we can define them in a more or less free manner. In particular, there is no dependency on multiplicitly of functions (single-valued or multi-valued) and there can be cycles of functions. In COM all single-valued dimensions are upward directed while multi-valued inverse dimensions are downward directed. • FDM does not have a canonical semantics in the sense of COM and hence inference and complex manipulations are very limited. • The system of types in FDM is closer to the conventional OO approach.
