Implementing Model-Based Data Structures using Transient Model Extensions

Software is often constructed using a layered approach to encapsulate various functionality in corresponding layers. Individual requirements of each layer demand layer specific data structures. These data structures typically provide redundant information with respect to the data source. Providing a Model Driven Software Development approach for creating these data structures leads to overlapping data models, each containing data structures defined by the data source. Because putting all various requirements of the software layers in a single data model can lead to difficulties, each software layer should only extend the basic data source model with its specifically needed model elements. The approach presented in this paper applies a mechanism for a dynamic extension of a data model. This extension mechanism is used in the implementational activity of a software process, and allows the changing of a model within a local scope. Using this mechanism, a basic data model can be used by every layer, being extended by additional attributes and classes for satisfying layer specific requirements.