Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!usc!elroy.jpl.nasa.gov!ncar!hsdndev!husc6!bunny!mto From: mto@GTE.COM (Tamer Ozsu) Newsgroups: comp.databases Subject: Re: Object Oriented Model and Hierarchical Model Keywords: Difference Message-ID: <10123@bunny.GTE.COM> Date: 30 Nov 90 13:36:31 GMT References: Organization: GTE Laboratories, Waltham MA Lines: 43 In article chappidi@caip.rutgers.edu (Rajendra Chappidi) writes: > >Is there a difference between the Object Oriented model and >Hierarchical Model at all or are they one and the same ? > >If any one has an answer to this please let me know. > >Thanks, >Raj There is a short answer to this: "Yes, there is a world of difference", but the real answer (i.e., explanation of what the differences are) would take too long to do in a mail message. The network-based models and object-oriented models are sometimes confused to be the same thing because both of them are non-value based (as the relational model is). However, the differences are enormous. Briefly, the object-oriented models have data encapsulation, sharing (usually in the form of inheritance), multiple levels of abstraction, etc. What exactly are the features of an object-oriented data model is subject to discussion, but here are some references that should help: M. Atkinson, F. Bancilhon, D. DeWitt, K. Dittrich, D. Maier and S. Zdonik. " The Object-Oriented Database System Manifesto", In Proc. 1st Int. Conf. on Deductive and Object-Oriented Databases, Kyoto, Japan, 1989, pp. 40-57. S. Zdonik and D. Maier. Readings in Object-Oriented Database Systems, Morgan Kaufmann Publishers, 1990. [The authors have an introductory chapter at the beginning that should be very helpful.] W. Kim and F. Lochovsky. Object-Oriented Concepts, Databases and Applications, ACM Press, 1989. S. Khoshafian and R. Abnous. Object Orientation - Concepts, Languages, Databases, User Interfaces, Wiley, 1990. I am sure I did not list a ton of other very valuable sources. ==Tamer-- M. Tamer Ozsu mto@gte.com GTE Laboratories 40 Sylvan Road Waltham, MA 02254 Brought to you by Super Global Mega Corp .com