Databases Reference
In-Depth Information
CHAPTER
9
APPROACHES
LEARNING OBJECTIVES
Objectives
Describe distributed database management systems (DDBMSs)
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Discuss client/server systems
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Examine the ways databases are accessed on the Web
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Discuss XML and related document specification standards
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Define data warehouses and explain their structure and access
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Discuss the general concepts of object-oriented DBMSs
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INTRODUCTION
In previous chapters, you learned about relational DBMSs (RDBMSs), which dominate the database market today. In this
chapter, you will examine several database management topics, most of which are applicable to relational systems.
The centralized approach to processing data, in which users access a central computer through personal computers (PCs)
and workstations, dominated organizations from the late 1960s through the mid-1980s because there was no alternative
approach to compete with it. The introduction of reasonably priced PCs during the 1980s, however, facilitated the placement of
computers at various locations within an organization; users could access a database directly at those locations. Networks
connected these computers, so users could access not only data located on their local computers but also data located
anywhere along the entire network. In the next section, you will study the issues involved in distributed databases where a
database is stored on more than one computer.
Organizations often off-load, or shift, data communications functions from central computers to smaller computers to
improve processing speed. Similarly, organizations often use client/server systems to off-load database access functions from
central computers to other computers; you'll study these client/server systems. You will also learn about accessing databases
on the Web and the growing importance of XML and related document standard specifications. Then you'll learn about special
