text: Home -> Community -> Usenet -> comp.databases.theory -> Re: Pizza Example
  "Anthony W. Youngman" <wol_at_thewolery.demon.co.uk> wrote in message news:0IV6pcCYeDhAFwEv_at_thewolery.demon.co.uk...
  > In message <2HQgc.9747$gG5.9105_at_newssvr31.news.prodigy.com>, Eric Kaun
  > <ekaun_at_yahoo.com> writes
  > >"Anthony W. Youngman" <wol_at_thewolery.demon.co.uk> wrote in message
  > >news:ym$bCWJIqvfAFw3f_at_thewolery.demon.co.uk...
  > >Good question; in this case I meant simple as advocated by Occam's Razor.
  > >Fewer concepts, and more consistent notation.
  >
  > Occam's razor - as phrased by ?Einstein - "Things should be as simple as
  > possible - but no simpler".
  Agreed.
  > To me, relational has simplified too far - "The car is blue and green",
  > "John is Mike's dad". If I model both these situations in relational, I
  > need a relation to link the colours to the car. I need a relation to
  > link John and Mike. In the first situation I'm linking an entity with
  > its attributes. In the second I'm linking two entities. Relational makes
  > no distinction between the two types of link ...'m not just being argumentative. I think it's a credit to relational that it (tries to) base itself on predicates, as opposed to entities, relationships, and attributes, is stronger for many reasons covered in books already mentioned...
  > > "the data" is
  > >what the entire disagreement is about. Is it a set of attribute values?
  Is
  > >it an object graph? Is it both, meaning we've decided in advance the view
  of
  > >"the object" everyone must have because it's "real world" (can you define
  > >that?).
  >
  > Typically, it's a set of attribute values. And yes, I see what you mean
  > - given the primary key, a relational view will return (after a lot of
  > work if it's scattered across many tables) all the attributes associated
  > with an entity. With Pick, it is a single "row" in a single "table".
  And the decision of what "it" you're talking about is likely to be premature and limited in usefulness. The up-front simplicity of modeling based on entities is undercut by its application focus.
  > Well, yes, the fact that in relational N is only ever 2 makes life
  > simple.
  HA! So you admit it? :-)
  > But that's a "cosmological constant" which upsets purist
  > physicists. If I can solve a problem for N where N is any number, it's a
  > far better solution than if it only works for "N=2" :-) (and actually,
  > both the values you've quoted for N I've met in practice :-)
  Uh... I suspect there's another model / meta-model confusion here, but the margin of this message is too narrow to contain the marvelous proof I've concocted.
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