Information Technology Reference
In-Depth Information
6.6.4 Modeling the System
Analysis modeling uses a combination of text and diagrammatic forms to depict
requirements for data, functions, and behaviors in a way that is relatively easy to
understand, and, more importantly, straightforward to review for correctness,
completeness and consistency. This section presents resources for conventional
and object-oriented analysis (OOA) methods as well as resources for UML.
Data modeling is a method used to define and analyze data requirements needed
to support the business processes of an organization. The data requirements are
recorded as a conceptual data model with associated data definitions. Actual
implementation of the conceptual model is called a logical data model. To
implement one conceptual data model successfully, may require the implemen-
tation of multiple logical data models. Data modeling defines the relationships
between data elements and structures. Data modeling techniques are often used to
model data in a standard, consistent, predictable manner in order to properly
manage it as a resource. The use of this standard is strongly recommended for all
projects requiring a standard means of defining and analyzing the data resources
within an organization. Such projects include:
• Incorporating a data modeling technique into a methodology;
• Using a data modeling technique to manage data as a resource;
• Using a data modeling technique for the integration of information systems;
• Using a data modeling technique for designing computer databases.
Data modeling may be performed during various types of projects and in
multiple phases of the projects. Data models are progressive; there is no such thing
as the final data model for a business or application. Instead a data model should be
considered a living document that will change in response to a changing business.
The data models should ideally be stored in a repository so that they can be
retrieved, expanded and edited over time. Bentley (
2004
) determined two types of
data modeling:
• Strategic data modeling: This is part of the creation of an information systems
strategy, in which an overall vision and architecture for information systems is
defined. Information engineering is a methodology that embraces this approach.
• Data modeling during systems analysis: In systems analysis, logical data models
are created as part of the development of new databases.
6.6.5 Class Diagrams
We have described class diagrams in previous chapters. In this section, we will
review that information in a way that is relevant to the analysis phase. Class
diagrams are used to describe a class based on the elements that make it up, as well
as its relationships to other classes. In a previous chapter, we said that class
