Database Reference
In-Depth Information
•
End-user applications are easy to develop and build.
You can spend more time on
programming and addressing the data manipulation tasks at hand, instead of work-
ing around the inevitable problems that arise when you work with a poorly de-
signed database.
Database Design Methods
Traditional Design Methods
In general, traditional methods of database design incorporate three phases:
requirements
analysis, data modeling,
and
Normalization
.
The requirements analysis phase involves an examination of the business being modeled,
interviews with users and management to assess the current system and to analyze future
needs, and an assessment of information requirements for the business as a whole. This
process is relatively straightforward, and, indeed, the design process presented in this topic
follows the same line of thinking.
The data modeling phase involves modeling the database structure using a data modeling
method, such as entity-relationship (ER) diagramming, semantic-object modeling, object-
role modeling, or UML modeling. Each of these modeling methods provides a means of
visually representing various aspects of the database structure, such as the tables, table re-
lationships, and relationship characteristics. In fact, the modeling method used in this topic
isabasicversionofERdiagramming.
Figure2.1
showsanexampleofabasicERdiagram.
Figure 2.1. An example of a basic ER diagram
Note
I've incorporated the data modeling method I use in this topic into the design pro-
cess itself rather than treating it separately. I'll introduce and explain each model-
ing technique as appropriate throughout the process.
Each data modeling method incorporates a set of diagramming symbols used to represent
a database's structure and characteristics. For example, the diagram in
Figure 2.1
provides
information on several aspects of the database.
• The rectangles represent two tables called AGENTS and CLIENTS.
