Re: One-To-One Relationships

On Dec 4, 5:20 pm, Jan Hidders <hidd..._at_gmail.com> wrote:
> On 4 dec, 21:55, vldm10 <vld..._at_yahoo.com> wrote:
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> > On Dec 3, 6:01 am, Jan Hidders <hidd..._at_gmail.com> wrote:
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> > > On 2 dec, 18:53, vldm10 <vld..._at_yahoo.com> wrote:
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> > > > On Dec 2, 4:36 am, Jan Hidders <hidd..._at_gmail.com> wrote:
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> > > > > On 1 dec, 06:26, vldm10 <vld..._at_yahoo.com> wrote:
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> > > > > > On Nov 30, 9:34 am, Jan Hidders <hidd..._at_gmail.com> wrote:
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> > > > > > > Why by only one attribute? Why not by a set of attributes? Or a
> > > > > > > combination of attributes and relationships (as is the case for weak
> > > > > > > entities)?
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> > > > > > This is OK, but my advice to you -don't use it often.
> > > > > > I will give you one example:
> > > > > > The relation has A1, A2, A3, A4 "attributes" and they are mutually
> > > > > > independent (i.e. they are in BCNF)
> > > > > > The "attributes" can change their values for "entity" like in
> > > > > > "temporal DB". User needs on line all information for any "entity" in
> > > > > > any moment.
> > > > > > Can you please write the key for this relation so that we can discuss
> > > > > > it.
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> > > > > You do realize we were talking about ER modeling, not RM modeling,
> > > > > don't you?
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> > > > Here in this tread it is about E/R and RM as well as relationship
> > > > among them and I also used terms "entity" and "attribute".
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> > > My remark that you responded to was only about ER modelling.
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> > I tried to explain my answer through an example.
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> You formulated the explanation of your answer to an issue in ER
> modeling in RM terminology. If you would have formulated it in ER
> terminology that might have helped you considerably to make your
> point. RIght now I still don't have a clue what you are trying to tell
> me or even whether it is actually relevant for the question at hand.
>
> -- Jan Hidders- Hide quoted text -
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> - Show quoted text -

Did you read on my web site recomendeded part: "7.1 Identifying the Plurality" ?

Vladimir Odrljin Received on Wed Dec 05 2007 - 00:03:13 CET