[Year 12 IT Apps] Exam: 1NF???

Mon Nov 10 17:17:58 EST 2014

Hello all

There is a good reason for going for 1NF first: you cannot be 2NF without first being 1NF, and you cannot be 3NF without first being 2NF.
So, asking a question about 1NF seems quite reasonable because that's where it all starts (by the way, I  haven't seen the question yet so I cannot comment on its quality).
And if you don't know what the normal forms are, how can it happen as part of 'sensible' design? So, at least at a definitional level, students need to know what 1NF, 2NF and 3NF are. As to whether they should be able to move from one to another is a different question.

Regards
Robert T-A
  ----- Original Message ----- 
  From: Robert Hind 
  To: Year 12 IT Applications Teachers' Mailing List 
  Sent: Sunday, November 09, 2014 1:09 PM
  Subject: Re: [Year 12 IT Apps] Exam: 1NF???

  I'd like to pick up on this point:

  "Isn't it ideal to design databases to be 3NF compliant in the first instance? Why bother with this step? Is the purpose of this question to merely see if students instance what 1NF is? "

  I have been involved with teaching IT and also with database design for many years. Have never taught normalisation or even thought about it as a process. It just happens as part of (sensible) database design.

  The whole idea of 1NF, and afterwards 2NF and 3NF, goes back to Codd in 1971. Surely by now we should be designing databases along sensible lines that do end up with "3NF compliant" databases but frankly without all that hassle about "normalisation"as a process in itself.

  Robert Hind
  Retired
  Ex Traralgon and Ashwood

  Subject: Re: [Year 12 IT Apps] Exam: 1NF???

    On 7 November 2014 22:42, Poke, Michael C <poke.michael.c at edumail.vic.gov.au> wrote:

    <snip>

      But my one main issue is with this 1NF question. My simplest response to this question is "why?". 

    I wondered the same, since the result is obviously inadequate to make the table at all useful

      Isn't normalising to 1NF unnecessary and bad practice? 

    Only if you stop there and don't go on to 3NF (Reminds me of the Holy Hand Grenade in The Life of Brian...)
      Isn't it ideal to design databases to be 3NF compliant in the first instance?  Why bother with this step?  Is the purpose of this question to merely see if students instance what 1NF is?  

    I suspect it is. It seems they were trying to ease off normalisation for this year at least. 
    But to normalise that horrible table to only 1NF is completely pointless and artificial without going on to 2NF...
    Like asking art students to paint a face without eyes.

    Without 2NF and more tables, the mixing of interestgroups data and contactlist data in a single record is ridiculous, and I can't see a reasonable solution that would make the data useful. Expanding a single field (like interestgroups) into 3 new records would let the kids show they understand 1NF, but why add another similar field to just make it awfully messy and difficult, for no greater demonstration of 1NF knowledge?

    I can't work out whether the examiners were looking for this...

    or - as Gary has suggested -  15 records, repeating each interest group 3 times to add the contactlist data. And that's a LOT of writing for 3 marks.

    Whichever way you choose, the result is an ugly, unusable mess.
    The question should have limited itself to one repeating field and left the other one well out of it.

      At least it was only 3 marks and not 6 or 8 like other years. 

    Yes, that was a relief.
    The fact that it was only worth 3 marks - and the space provided for the answer was only a third of a page - suggests to me that they were expecting the shorter answer I showed above. But that's a guess.

    *I* would not have written 15 lines for 3 marks, I can tell you!

    -- 

    Mark Kelly
    mark AT vceit DOT com
    http://vceit.com

    I love the sound of people's voices after they stop talking.

    I, Mark Kelly, am entirely responsible for the offensive verbiage I spew forth.
    Have I offended anyone with this post?  I would not be surprised.
    If offended, please whinge to me at the email address above. 
    Please leave poor Kevork alone.  It is not his fault.

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  http://www.edulists.com.au - FAQ, resources, subscribe, unsubscribe
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