Path: newssvr20.news.prodigy.com!newsmst01.news.prodigy.com!prodigy.com!rip!news.webusenet.com!peer01.cox.net!cox.net!border3.nntp.aus1.giganews.com!intern1.nntp.aus1.giganews.com!nntp.giganews.com!nntp.golden.net!news.golden.net.POSTED!not-for-mail NNTP-Posting-Date: Thu, 09 Oct 2003 21:34:06 -0500 From: "Bob Badour" Newsgroups: comp.databases.theory,comp.databases.object,comp.databases References: Subject: Re: Introducing PlayDB (The Model, The Language, The DBMS) Date: Thu, 9 Oct 2003 22:33:15 -0400 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Forwarded: by - (DeleGate/8.7.2) Message-ID: Lines: 31 NNTP-Posting-Host: 199.166.210.182 X-Trace: sv3-0ehzzmH1k186o+oaDC7GQqBftsvMN07+0gFRG+ck4xtSS22GB6lPnFgZMG6fH/BJ5Z9pGp9cVjAMvp6!I7E8ALSYkwHqPZ2jDGBHSmMTQnYg/OsBEMXf1+aD3Ee1B7OSfKoiNG+j4Z5E3OPDqe32N80NqK8= X-Complaints-To: abuse@golden.net X-DMCA-Complaints-To: abuse@golden.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.1 Xref: newssvr20.news.prodigy.com comp.databases.theory:21692 comp.databases.object:16509 comp.databases:48158 Read Date's and Darwen's _The Third Manifesto_, the book and not the 1995 paper, for a sound type inheritance model. "Seun Osewa" wrote in message news:ba87a3cf.0310091820.50180857@posting.google.com... > Based on my own observations, I would like to define a class as: > > "A set of Objects/Entities percieved to have certain similar > properties." > > In this definition there is no notion of hierarchy because that's the > way it is in real life. A square is a rhombus, a rhombus is a > parallelogram. A square is also a rectangle, which is not a rhombus, > but is a parallelogram. So we would have difficulty defining one > "superclass" for square. Then of course a parallelogram could turn > out to be a rhombus on resizing, a rectangle could become auitable to > join the group of squares on resizing, etc. And I think this is just > the case in real world that the classES an object belongs to can also > be dynamic. And when you look at the relational model, well, it > requires you to choose a type for each item of data. > > What if an object could be a member of any arbitrary set of classes? > What if this mapping of object to class was totally dynamic? It > reminds me of interfaces in Java programming where an object can > export an infinite number of interfaces, only that of course all this > is dome at compile-time. Things could be come more > complicat....err... interesting! > > Seun Osewa.