| Summary: | It is well agreed that the conventional database models provide limited semantic expressiveness.
These models are designed to enable mapping to simple data constructs,
which provide for the expression of only a limited part of the domain knowledge. However,
one of the reasons for the proliferation of the entity-relational model is the ease in
which the mapping of logical structures to physical structures is done. In this paper we
suggest a data model which gives new means for expressing the semantics of data. We
demonstrate how this data model can be mapped to the traditional relational model
in order to demonstrate its practical appeal. In constructing our model we use the
framework of BWW ontology, and emphasis two of its principles. The first principle
we follow is that often properties share an important relationship- the relation of precedence.
We believe that enabling users to express precedence information and assuring
precedence consistency can provide important means for semantic expressiveness. The
second principle we follow, is that of separating classification information from entity
information. By assuring this ontological principle we enable different users to have
different views of the world while sharing data. The combination of these two principles
in the data model provides interoperability and evolutionary benefits. Users can
concentrate on the commonalities between their view of the enterprise and views of
other users. Updates to the database are propagated across different views, and the
meaning of information can be extracted. This paper analyses theoretical issues concerning
the need for such a model, as well implementation issues such as Metadata
constructs, DDL/DML commands, and implicit operations that may be done in the
DBMS in order to support such a data model.
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