Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!murtoa.cs.mu.oz.au!munnari.oz.au!otc!metro!cavs!johng From: johng@cavs.syd.dwt.oz (John Gardner) Newsgroups: comp.databases Subject: Re: Relational Model Keywords: relational empirical support Message-ID: <826@cavs.syd.dwt.oz> Date: 1 Aug 89 02:27:52 GMT References: <18886@sequent.UUCP> <19101@sequent.UUCP> <172@bms-at.UUCP> Reply-To: johng@cavs.UUCP (John Gardner) Organization: CSIRO Division of Wool Technology, Ryde, Sydney, Australia. Lines: 22 > >One thing in the relational model I disagree with: Duplicate records are >useless in any order. All tables should be required to have a "UNIQUE" >combination of fields. After all, we are dealing with *sets*, not *bags*. :-) This is precisely what the relational model defines. When the relational model says we have a set of tuples, it means that each tuple must be unique. There is an implicit "UNIQUE" in that all the fieilds combined must be unique. -- /*****************************************************************************/ PHONE : (02) 436 3438 ACSnet : johng@cavs.dwt.oz #include -- /*****************************************************************************/ PHONE : (02) 436 3438 ACSnet : johng@cavs.dwt.oz #include