THE DATABASE APPROACH - Database Design and Development: An Essential Guide for IT Professionals - page 28

tures of data integrity, reliability, and recovery found in the relational realm. We will
cover object-relational database systems in greater detail in Chapter 20.

TYPES OF DATABASES

By now you are convinced of the significance of information for an organization.
You know that information is a key corporate asset and that it has to be managed,
protected, and used like any other major asset. The corporate database that holds
an organization's data is the underlying foundation for corporate information.
Organizations are also faced with questions regarding how and where to hold the
corporate data.
Where should an enterprise hold its data? Should all the corporate data be kept
centrally in one place? If so, what are the advantages and disadvantages? Or should
the corporate data be divided into suitable fragments and the pieces kept at differ-
ent locations? What are the implications of this arrangement?
Organizations primarily adopt one of two approaches. If the entire database is
kept in one centralized location, this type of database is a centralized database. On
the other hand, if fragments of the database are physically placed at various loca-
tions, this type of database is a distributed database. Each type has its own benefits
and shortcomings. Again, whether an enterprise adopts a centralized or a distrib-
uted approach depends on the organizational setup and the information require-
ments. Let us review the two types.

Centralized

Figure 1-11 illustrates a centralized database.

Enterprise
Database

All data at a single site.
Data access from remote sites
through communication links.
Easy to administer.
Uncertain data availability.

Common Examples :
Personal Database
Central Computer Database
Client / Server Database

Figure 1-11 Centralized database.