Information Modeling and Relational Databases, 2nd Edition

14.3. Nesting, Coreferencing, and Flattening

As humans, we have the freedom to think of the universe in different ways. One choice in modeling is whether to represent some feature in terms of an object type, and if so, how. The previous section discussed how to absorb or extract object types by predicate specialization and generalization. An object type with a composite identification scheme may be portrayed explicitly either as a nested object type or as a co-referenced object type. If we don’t want to think of this feature in terms of an object type, we can model it with predicates using a flattened approach. This section we consider transformations among nested, coreferenced, and flattened approaches.

Let’s start with a familiar example. ...