  In this paper we describe a new approach to data modelling called the
concept-oriented model (CoM). This model is based on the formalism of nested
ordered sets which uses inclusion relation to produce hierarchical structure of
sets and ordering relation to produce multi-dimensional structure among its
elements. Nested ordered set is defined as an ordered set where an each element
can be itself an ordered set. Ordering relation in CoM is used to define data
semantics and operations with data such as projection and de-projection. This
data model can be applied to very different problems and the paper describes
some its uses such grouping with aggregation and multi-dimensional analysis.
