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Elementary Key Attributes


Elementary Key Attributes

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John Mitchell-245523
John Mitchell-245523
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L' Eomot Inversé (10/5/2011)
I find it quite frightening that so few people know enough about normalisation to get this one right.

I don't. This question is couched in abstract language. "Elementary key", "prime attribute"and "fixed" aren't part of the everyday SQL Server vernacular. Don't get me wrong - I'm not complaining, since I found it an educational experience. I just think more people would have got it right if the terminology had been a bit more familiar.

John
Steve Jones
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Updated the question to say "select 3". My apologies for missing that.

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Good question, got it right but only after flip flopping back and forth on a couple of the choices because the verbage was so close.

Really god tthe juices going.

thanks

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Stewart "Arturius" Campbell
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Thanks, Tom
This really got my mind working.
Definitely learned something new today .

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Rob Schripsema
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Who can explain why the fifth option, "A on its own is a candidate key of T" is NOT true? What am I missing here?

Rob Schripsema
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Sean Lange
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John Mitchell-245523 (10/5/2011)
L' Eomot Inversé (10/5/2011)
I find it quite frightening that so few people know enough about normalisation to get this one right.

I don't. This question is couched in abstract language. "Elementary key", "prime attribute"and "fixed" aren't part of the everyday SQL Server vernacular. Don't get me wrong - I'm not complaining, since I found it an educational experience. I just think more people would have got it right if the terminology had been a bit more familiar.

John


I agree John. The vernacular was outside the scope of normal conversation far enough that I struggled to understand what the answers meant.

Great question Tom!!! Certainly an educational question.

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TomThomson
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paul s-306273 (10/5/2011)
Not quite sure of the relevance of this question.

(Or is that just sour grapes - 2correct answers, 118 incorrect answers so far!)

Well, it's the second question of a pair about normalisation theory; the first will appear in about a week's time. (Steve's ways are sometimes hard to follow - but I'm not complaining, I saw that they would appear in the wrong order but didn't get around to asking him to change it, so it's my fault.)

My idea was to put a couple of questions that would go well with the fourth article on my series about normalisation. This is somewhat screwed up by the fact that I wrote an appallingly bad draft of the fourth article (so bad that Steve hasn't yet commented on it, probably because he would be embarrassed to tell me how bad it is) and haven't yet sorted it out, so the questions are appearing before the article insetad of after it.

It is really worrying that people don't unsterstand the representation principle (the base of all early work on normalisation - everything up to and including third normal form) and how normalisation adheres to it as far as elementary key normal form but abandoned it in Boyce-Codd normal form (and all higher normal forms) so that for many situations it is better to have a schema that has some tables not in BCNF or any higher normal form although most of the tables should conform to higher normal forms, because this lack of understanding of basic normalisation principles encourages schema designs that accomodate coding bugs with no error messages that with proper schema design would violate declared constraints.

Tom

john.arnott
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hodgy (10/5/2011)
Ah, I was researching elemenTARTY keys, probably why I got it wrong ;-)

I saw that too and looked for one of the choices to be "A must equal a multiple of 3.14159265358979323846264338327950288419716939937510".:-)
TomThomson
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John Mitchell-245523 (10/5/2011)
L' Eomot Inversé (10/5/2011)
I find it quite frightening that so few people know enough about normalisation to get this one right.

I don't. This question is couched in abstract language. "Elementary key", "prime attribute"and "fixed" aren't part of the everyday SQL Server vernacular. Don't get me wrong - I'm not complaining, since I found it an educational experience. I just think more people would have got it right if the terminology had been a bit more familiar.

John

I wish I knew some more familiar terminology. I suppose for "prime attribute" one can use "key attribute" (although the SQL influence on terminology means that a key attribute may allow nulls that case is covered bu other options) but "fixed" is just normal English (or American) and I'm not aware of any other term at all for "elementary key".
If you can suggest any better terms, I'll be glad to hear them - and will maybe use them in an article soon.

Tom

SanDroid
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Nice question on Normalization. Would have been easier to answer if I knew that T was part of a database at BCNF or EKNF.
Thought I selected the right answers A,C,D but saw the "you are wrong" response.
I guess I need more coffee and less insomnia. Cool
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