Path: text.usenetserver.com!out04b.usenetserver.com!news.usenetserver.com!in02.usenetserver.com!news.usenetserver.com!postnews.google.com!news2.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!nx01.iad01.newshosting.com!newshosting.com!post01.iad01!news.aliant.net!not-for-mail Date: Tue, 18 Dec 2007 08:06:31 -0400 From: Bob Badour User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.databases.theory Subject: Re: Another view on analysis and ER References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Lines: 32 Message-ID: <4767b7c9$0$5271$9a566e8b@news.aliant.net> NNTP-Posting-Host: 142.176.114.224 X-Complaints-To: abuse@aliant.net Xref: usenetserver.com comp.databases.theory:168313 X-Received-Date: Tue, 18 Dec 2007 07:06:34 EST (text.usenetserver.com) David Cressey wrote: > "rpost" wrote in message > news:c1f35$4766eca5$839b4533$16718@news1.tudelft.nl... > >>David Cressey wrote: >> >>[...] >> >>>The question of whether it's "the same entity" or "a different entity " > > is > >>>also moot. >> >>Until you consider other relations referring to the same entity. >>Their attributes may or may not have to be updated as well. > > Are they really "referring to the same entity"? Or are they "referring to > data values that describe and/or identify some entity"? Can an entity be > identified without data? That depends on your definition of data. Can you identify yourself if nothing about you has been represented suitably for machine processing? I think you can. You can probably even communicate that identity to another human without representing anything suitably for machine processing. You can probably even identify Grandpa's Axe with a grunt and a gesture. However, we cannot manage data without data, and database theory is all about managing data.