Comparison of Object and Relational Concepts
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