Database Reference
In-Depth Information
CHAPTER 12
THE PHYSICAL DESIGN PROCESS
CHAPTER OBJECTIVES
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Study the transition to physical design from logical design
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Understand how physical design conforms to the target DBMS
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Learn the physical design process for the relational database
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Discuss storing of data on physical storage
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Examine various indexing techniques to improve data access
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Identify special performance considerations
With Chapter 11, our discussions on logical design have to come to a state of
completion. You now know the purpose of the logical design process; you have
reviewed the steps, and you have learned the steps and tasks of the process.
First, you model the information requirements by creating a semantic data model.
Then you complete the logical design process by transforming the semantic data
model into a conventional data model such as the relational, hierarchical, or
network data model. Because the relational data model is superior to the others
and because it is widely used, we emphasized the relational data model in our
discussions. You have also studied two data modeling techniques for creating a
semantic data model—the object-based data modeling and entity-relationship data
modeling techniques.
Remember that a semantic data model is a generic data model. It has no rela-
tional, hierarchical, or network flavor. A semantic data model does not consist of
tables with rows and columns; only a relational data model does. Only when
you move from a semantic data model to a conventional data model such as the
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