Doi: 10.1145/1400181.1400195

How do we apply the concept of resource
orientation by designing representations
to support interactions?
By eRik wiLDe anD RoBeRt J. GLushko
Document
Design
matters
THE CLASSICAL APPROACH to the data aspect of system
design distinguishes conceptual, logical, and physical
models. Models of each type or level are governed by
metamodels that specify the kinds of concepts and
constraints that can be used by each model; in most
cases metamodels are accompanied by languages for

describing models. For example, in database design, conceptual models usually conform to the Entity-Relationship (ER) metamodel (or some extension of it), the logical model maps ER models to relational tables and introduces normalization, and the physical model handles implementation issues such as possible denormalizations in the context of a particular database schema language. In this modeling methodology, there is a single hierarchy of models that rests on the assumption that one data model spans all modeling levels and applies to all the applications in some domain.^a

a This simplified view may change if different implementations of the same conceptual model use different lower-level models, per-

The “one true model” approach assumes homogeneity, but that does not work very well for the Web. The Web as a constantly growing ecosystem of heterogeneous data and services has challenged a number of practices and theories about the design of IT landscapes. Instead of being governed by “one true model” used by everyone, the underlying assumption of top-down design, Web data and services evolve in an uncoordinated fashion. As a result, a fundamental challenge with Web data and services is matching and

 

haps for performance optimization reasons. In this case, the lower-level models are derived from the conceptual model, but they are also based on different assumptions about access patterns and required performance.