Data Warehousing Fundamentals for IT Professionals

CHAPTER 18

THE PHYSICAL DESIGN PROCESS

CHAPTER OBJECTIVES

• Distinguish between physical design and logical design as applicable to the data warehouse
• Study the steps in the physical design process in detail
• Understand physical design considerations and know the implications
• Grasp the role of storage considerations in physical design
• Examine indexing techniques for the data warehouse environment
• Review and summarize all performance enhancement options

As an IT professional, you are familiar with logical and physical models. You have probably worked with the transformation of a logical model into a physical model. You also know that completing the physical model has to be tied to the details of the computing platform, the database software, hardware, and any third-party tools.

As you know, in an OLTP system you have to perform a number of tasks for completing the physical model. The logical model forms the primary basis from which the physical model is derived. But, in addition, a number of factors must be considered before you can get to the physical model. You must determine where to place the database objects in physical storage. What is the storage medium and what are its features? This information helps you define the storage parameters. Then you have to plan for indexing, an important consideration. On which columns in each table must the indexes be built? You need to look into other methods for improving performance. You have to examine the initialization parameters in the ...