[Year 12 IT Apps] IT Apps Exam, Short Answer, Question 7A

[Mark]

>
> *From:* itapps-bounces at edulists.com.au [mailto:
> itapps-bounces at edulists.com.au] *On Behalf Of *Vear, Gary D
>



> Will students be penalised if they do the sensible thing and normalise
> this data to 2NF by creating separate tables?
>
> I'd appreciate feedback/corrections from others on this question, since it
> has me somewhat confused.
>

I fear that a student who (logically and properly) translated the table to
2NF *would* be penalised since the question asked for knowledge of *1NF*.
Any 1NF solution (with a single, ugly table) would be technically correct
(no repeating fields, one datum per field) but completely useless as a
table.

That's what chews my Chihuahuas.

Normalising to 1NF is a completely artificial exercise. Normalisation is a
destination, and the 1,2,3 steps are purely *logical* - not practical -
stages, simply to aid theoretical elucidation.

In practice, you *never* start with 1NF, proceed to 2 and fix things up
with 3.

For a start, 2NF problems are never even going to happen if you start every
new table with a key field.
Bang.
Problem solved.
No multiple-field keys, so no 2NF issues.

If you *start* a database design with an understanding of 2NF you never
need to experience 2NF problems.
I know *theoretically* that falling into an open sewer is not good. I don't
need to be *pushed *into the cesspit to see if I know how to get out.
I side-step it before I get to it.

Similarly, you don't start a database by throwing fields together
carelessly and then sorting problems out later, step by step.

Slave: Here, mighty Pharaoh. We have finished your million-ton tomb.
Pharaoh: O goody. Does it have a burial chamber in it?
Slave: O dear. Give us twenty years. We'll fix it. Then you can ask if the
pointy end is at the top or not.

I know that the examiners want to test whether students understand the
logic behind attaining 1NF.
That's great. I love them for it.
Capable students could easily and quickly have shown their understanding of
1NF in this exam if they'd been given a a table with *one* repeating field.

But to add the *second* repeating field? That was just ugly and unnecessary.

Student: "Of course I know 1NF. I split the repeating values into new
records... but what the hell do I do with the second repeating field? I
can't meaningfully fix that with a single table. I'd need to get to 2NF to
do that. I can't do anything sensible with a single table. What am I
supposed to do? OK. I'll go to 2NF and lose all my marks..."

The question mistakenly assumed that having 2 repeating fields would be
twice as hard as having 1 repeating field.

Wrong. The level of difficulty was exponential, not additive

I feel better now.

-- 

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.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.edulists.com.au/pipermail/itapps/attachments/20141110/20ad09b2/attachment.html