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Part II: Building Databases and Working with Data
Database Basics .................................................................................................
The purpose of a database is to store the information required by an organization. Any
means of collecting and organizing data is a database. Prior to the Information Age,
information was primarily stored on cards, in fi le folders, or in ledger books. Before the
adding machine, offi ces employed dozens of workers who spent all day adding columns
of numbers and double-checking the math of others. The job title of those who had that
exciting career was computer.Author’s Note
Welcome to the second of three chapters that deal with database design. Although they’re spread out
in the table of contents, they weave a consistent theme that good design yields great performance:■ (^) Chapter 2 provides an overview of data architecture.
■ (^) Partitioning the physical layer is covered in Chapter 49, “Partitioning.”
■ (^) Designing data warehouses for business intelligence is covered in Chapter 51, “Business
Intelligence Database Design.”
There’s more to this chapter than the standard “Intro to Normalization.” This chapter draws on the
lessons that have been learned over many years.
This chapter covers a book’s worth of material, but concisely summarizes the main ideas. The chapter
opens with an introduction to database design terms and concepts. Then the same concept is presented
from three perspectives: fi rst, with the common patterns, then with a custom Layered Design concept,
and lastly with the normal forms. Each of these ideas is easier to comprehend after you understand
the other two, so if you have the time, read the chapter twice to get the most out of it.
As the number crunching began to be handled by digital machines, human labor, rather
than being eliminated, shifted to other tasks. Analysts, programmers, managers, and IT
staff have replaced the human “computers” of days gone by.
Benefi ts of a Digital Database
The Information Age and the relational database brought several measurable benefi ts to
organizations:
■ (^) Increased data consistency and better enforcement of business rules
■ (^) Improved sharing of data, especially across distances
■ (^) Improved ability to search for and retrieve information
■ (^) Improved generation of comprehensive reports
■ (^) Improved ability to analyze data trends
The general theme is that a computer database originally didn’t save time in the entry of
data, but rather in the retrieval of data and in the quality of the data retrieved. However,
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