Databases Reference
In-Depth Information
INTRODUCTION
This chapter focuses on the process of creating a data model. A
data model
rep-
resents real world business data in the form of a database design. The chapter
begins by introducing the design process, the main types of databases, and the
goals of data modeling. It then looks at the key components of a relational data-
base model: entities and relationships. The chapter concludes by comparing
some data models based on different businesses.
3.1 Understanding Database Design
Before you start designing your database, you need to know something about
the design process and what is involved. You need to understand how the data
will be used, so you must identify the database type, which will help define both
data and application requirements. You must also consider how business rules
can impact your final design.
3.1.1 Understanding the Design Process
Typically, database and application design is considered a three part process,
made up of
▲
Conceptual design
▲
Logical design
▲
Physical design
During the
conceptual design
(Figure 3-1), you lay the groundwork. This is
when you interview all of the
stakeholders,
which includes everyone with any
interest in the project, about their data requirements. This is when you identify
Figure 3-1
✍
✓
Conceptual Design
Logical Design
Physical Design
Data requirements
Information
requirements
Collection needs
Data locations
Logical framework
Applicable data
Data services
Data modeling
Physical modeling
Database objects
Object placement
Optimization
Conceptual design.
