OBJECT-ORIENTED DATABASE MANAGEMENT - Fundamentals of Database Management Systems - page 247

CHAPTER 9
OBJECT-ORIENTED
DATABASE MANAGEMENT
T raditional information systems and the applications within them have always
maintained a clear separation between their programs and their data. Programs
and data structures are designed separately, implemented separately, and stored
separately on disk. Relational databases fit very well into this arrangement. For a long
time the emphasis was on the programs, with the data structures and ultimately the data
stored in them being a secondary consideration. From a managerial point of view, the
concept of data as a corporate resource has made significant inroads into changing the
IS environment from this program-centric mentality into a more datacentric one.
On the technical side, an alternative approach to information systems and IS
development, which comes under the broad heading of ''object orientation,'' began
during the 1980s. This approach is, by its nature, more datacentric. It began with object-
oriented programming, then object-oriented systems analysis and object-oriented systems
design, and finally object-oriented database management, complete with object-oriented
database management systems (OODBMS). A variety of OODBMSs have been developed
and marketed commercially. We will take a brief look at the essential points of object-
oriented database management in this chapter, but, as we do, it is important to bear
in mind that the commercial OODBMSs vary widely in the OODBMS features that they
support either partially or fully.
OBJECTIVES
■ List several limitations in the relational database model.
■ Describe the object-oriented database concept.
■ Model data using such complex relationships as generalization and aggregation,
and such concepts as inheritance and polymorphism.
■ Describe the benefits of encapsulation.
■ Describe the value of developing abstract data types.
■ Explain what an object/relational database is.