o2, an object-oriented data model
The Altair group is currently designing an object-oriented data base system called O 2 . This paper presents a formal description of the object-oriented data model of this system. It proposes a type system defined in the framework of a set-and-tuple data model. It models the well known inheritance mechanism and enforces strong typing.
object-oriented data models model group data base systems paper formalism type system inheritance  framework 