Database Reference
In-Depth Information
superior compared to earlier data systems. Nevertheless, with newer types of appli-
cations, relational database systems tend to fall short on some types of information
requirements. For applications dealing with multimedia and spatial data, the
relational model is not quite adequate. The relational model limits the types of
data that can be defined and used. For engineering, scientific, office information,
and high-volume data retrieval systems, we need a more flexible and powerful
model than the relational model. The trend is toward extending the functionality
of relational database systems or going with a different orientation of data defini-
tions and rules for storage and retrieval. Object-oriented database systems and
object-relational systems have emerged to address the inadequacies of relational
systems.
Another significant area of interest in business circles relates to business intelli-
gence. Traditionally, for two decades or more, database systems helped organiza-
tions run their day-to-day business. With amplified complexity of business
conditions and increased data volumes, today's organization cannot perform its
business functions without database systems. Although information provided by
current database systems supports organizations in running everyday operations,
these systems cannot provide information in a form suitable for making strategic
decisions. Strategic decisions deal with major and far-reaching issues that help
companies set directions, make plans, and improve profitability. Database systems
are being adapted and used in business intelligence applications such as data
warehousing, data mining, and online analytical processing.
Database systems have also evolved to meet very specific requirements and to
be fitted with very specific functionalities. These are special-purpose or special-
function database systems. Such database systems, built with special properties and
functions, include parallel databases, active databases, intelligent databases, and so
on. There are also database systems intended for special purposes or special needs:
multimedia databases, mobile databases, geographic databases, and so on. We will
cover these kinds of specialized trends.
OBJECT-ORIENTED DATABASES
Let us begin with a broad definition. We may generally describe object orientation
as follows: software modeling and development methods that simplify construction
of complex systems with individual, reusable components. A main attraction of
object orientation consists of the ability to construct applications with standard,
reusable components.
What then are object-oriented databases? Object-oriented databases integrate
object orientation with database technology. Object orientation enables a more
precise, truer depiction of real-world objects. Therefore, object-oriented databases
provide a better representation of real-world information requirements than earlier
data systems. As you will see, object orientation allows a developer to hide the
details of implementation, concentrate on true representation, and share objects
usefully. Object-oriented databases combine the features of object orientation such
as abstract data typing and distinctive object identities with database capabilities
such as persistence, transaction processing, concurrency control, recovery, security,
and performance.
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