Path: dp-news.maxwell.syr.edu!spool.maxwell.syr.edu!drn.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.icl.net!newsfeed.fjserv.net!news.tele.dk!news.tele.dk!small.news.tele.dk!newsfeed.multikabel.nl!news2.euro.net!216.196.110.149.MISMATCH!border2.nntp.ams.giganews.com!nntp.giganews.com!feeder.enertel.nl!nntpfeed-01.ops.asmr-01.energis-idc.net!newshub3.home.nl!newshub1.home.nl!home.nl!not-for-mail From: Frank van Bortel Newsgroups: comp.databases,comp.databases.oracle.server Subject: Re: Beginner help needed in database design Date: Wed, 02 Feb 2005 22:36:22 +0100 Organization: @Home Benelux Lines: 49 Message-ID: References: <1106842617.933021@yasure> <1107199784.292798@yasure> Reply-To: fvanbortel@netscape.net NNTP-Posting-Host: cc28855-a.hnglo1.ov.home.nl Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: news5.zwoll1.ov.home.nl 1107380086 15580 212.204.168.125 (2 Feb 2005 21:34:46 GMT) X-Complaints-To: usenet@corp.home.nl NNTP-Posting-Date: Wed, 2 Feb 2005 21:34:46 +0000 (UTC) User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206) X-Accept-Language: en-us, en In-Reply-To: Xref: dp-news.maxwell.syr.edu comp.databases:43240 comp.databases.oracle.server:234842 Mark A wrote: > "Frank van Bortel" wrote in message > news:ctqf0h$2ln$1@news1.zwoll1.ov.home.nl... > >>SSN is a prime example is a technical key. Why is >>it people do not have a problem recognizing me by name, >>but computers do? >>-- >>Regards, >>Frank van Bortel > > > That is not true. Names are not unique (maybe yours is). For most people, > there is another person somewhere with the same exact name. Not true with > social security name or employee number (at least it is intended that these > are unique). > > Even when I was called John Doe (which is a common name in the US of A, I believe), people know me. The name may not be enough, but the features of my face, along with the name certainly do. And if that's too hard to understand/program for computers and uniquely identify me, how about my birth date, my father's and mother's names, and their birth dates? Or the fact I write to this ng, and have been doing that for about 10 years now? Chances are smaller than the number of people on this planet, that is not unique. But - it is not compact; in the times memory was scarce it surely would not have been acceptable. So, take a number. Nice and easy, small, and guaranteed to be unique on top of it all. And we call it: number. And as this particular number was invented by the (US) Social Service, let's call it a Social Security Number. I don't have one, but I live in a country with a civilized social security system :^) I've other numbers attached to me... But that is what a technical key is: a meaningless number (BTW: is SSN really meaningless, or is it coded?), instead of (mostly many) fields, together making up a unique identifier. -- Regards, Frank van Bortel