Path: dp-news.maxwell.syr.edu!spool.maxwell.syr.edu!drn.maxwell.syr.edu!news.maxwell.syr.edu!border1.nntp.dca.giganews.com!nntp.giganews.com!feed6.newsreader.com!newsreader.com!feed7.newsreader.com!newsreader.com!nntp.telenet.be!kwabbernoot.telenet-ops.be!phobos.telenet-ops.be.POSTED!not-for-mail From: Jan Hidders User-Agent: Mozilla Thunderbird 0.8 (X11/20040923) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.databases.theory Subject: Re: Base Normal Form References: <1120703075.535108.140280@o13g2000cwo.googlegroups.com> In-Reply-To: <1120703075.535108.140280@o13g2000cwo.googlegroups.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Lines: 27 Message-ID: Date: Thu, 07 Jul 2005 18:11:55 GMT NNTP-Posting-Host: 81.165.226.147 X-Complaints-To: abuse@telenet.be X-Trace: phobos.telenet-ops.be 1120759915 81.165.226.147 (Thu, 07 Jul 2005 20:11:55 MEST) NNTP-Posting-Date: Thu, 07 Jul 2005 20:11:55 MEST Organization: Telenet Internet Xref: dp-news.maxwell.syr.edu comp.databases.theory:32085 dawn wrote: > David Cressey wrote: > >>I'd like to suggest a new Normal Form definition, one that I'm calling Base >>Normal Form, for lack of a better term. >> >>The purpose is NOT to advance theory any further. It's to make it easier to >>teach introductory database design. >> >>Here it is: >> >> >>A table is in base normal form if and only if it has at least one candidate >>key. > > I think that what you are describing is a mathematical function > (sometimes referred to as a mapping), perhaps? I think that would be very confusing. First, his table actually has ordering, functions don't. Second, functions are binary relations, and even though you could interpret every n-ary relation as a binary relation, that is different from actually being the same. Finally, if there are multiple candidate keys then it actually represents several functions. It's really not a good idea to confuse the concept of relation and function. -- Jan Hidders