A comparison of relational and object model techniques is shown in the following table. It uses the concepts of data abstraction, inheritance, and encapsulation. Each of the links in the tables will open new windows containing more explanation.
|Object Model Concepts||Relational model concept||Object model concept||Object model benefits|
|Data Abstraction||Intersection entities and indexing to represent references between tuples||OIDS to directly represent references between objects||Simpler schema to represent complex data|
|Inheritance||Type codes||Class hierarchy||Direct representation of the references between type and subtypes as well as support for specialized processing for each subtype|
|Encapsulation||"If then else if" code based on type codes and management of the code, usually with libraries||Encapsulation provides built-in dispatching to ensure the correct code executes on the correct data||Reduced application code and reduced chance of error where the wrong code executes on the right data|
Also see Chapter 3 in the Object Database Handbook. That chapter has an extensive comparison of the two models.
More on the general topic: Comparing Object and Relational Models
Author: Douglas K Barry
You may use this material for your work or classes. Reprint Policy. Be sure to check the menu at the left for other articles available on this site.
The Savvy Manager's Guide
Douglas K Barry is also the author of a book that explains Web Services, service-oriented architecture, and Cloud Computing in an easy-to-understand, non-technical manner.
Web Services, Service-Oriented Architectures, and Cloud Computing: The Savvy Manager's Guide (Second Edition)
by Douglas K Barry with David Dick
This is a guide for the savvy manager who wants to capitalize on the wave of change that is occurring with Web Services, service-oriented architecture, and—more recently—Cloud Computing. The changes wrought by these technologies will require both a basic grasp of the technologies and an effective way to deal with how these changes will affect the people who build and use the systems in our organizations. This book covers both issues. Managers at all levels of all organizations must be aware of both the changes that we are now seeing and ways to deal with issues created by those changes.