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<title>Re: [Year 12 SofDev] SD Exam - Question 4</title>
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<p class=MsoNormal><span style='color:#1F497D'>That’s how my students read it
and I agree.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Laurie<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> sofdev-bounces@edulists.com.au
[mailto:sofdev-bounces@edulists.com.au] <b>On Behalf Of </b>Andrew Shortell<br>
<b>Sent:</b> Wednesday, 17 November 2010 1:45 PM<br>
<b>To:</b> Year 12 Software Development Teachers' Mailing List<br>
<b>Subject:</b> Re: [Year 12 SofDev] SD Exam - Question 4<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>Null - if there is nothing then what
is the point in proceeding further<br>
Type – if there is other than numbers then no point in doing any other checks<br>
Length – no point in checking the database if there is incorrect number of
digits<br>
Existence – checking the database is a significant step which goes outside of
the current program to an external source<br>
<br>
I have not yet seen the exam.. It is not offered here but as a teacher of
IS/SoD for a few years and lectured to 3rd year programmers this is how I would
approach it.<br>
<br>
Effectiveness in terms of why go to the next step when it has failed a step...<br>
It would be pretty silly to put it in the reverse order would n’t it...<br>
Check against the database before you even know if anything has been entered?
Etc<br>
<br>
Andrew<br>
<br>
<br>
-- <br>
Andrew Shortell <br>
(soon to leave Wallan SC)<br>
<br>
<br>
<br>
On 17/11/10 1:10 PM, "Mark KELLY" <<a
href="kel@mckinnonsc.vic.edu.au">kel@mckinnonsc.vic.edu.au</a>> wrote:</span><o:p></o:p></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Hi
all. I've started getting a bee in my bonnet (or a terrier in my
trousers) about Section C, Q4.<br>
<br>
<i>Percy is writing the program specification. For the section dealing with
entry of the Medicare number he writes<br>
<br>
If the user makes a mistake entering the Medicare number, the program has to
provide as much information as possible about what is wrong. Therefore include these
validation tests.<br>
Length - to make sure that the correct number of characters has been entered<br>
Existence - to make sure that the number entered exists on Medicare's database<br>
Null - to make sure something has been entered<br>
Type - to make sure that only numeric characters have been entered<br>
Note: These tests must be performed in the most effective order.<br>
<br>
a. Place these validation tests in the most effective order. 1 mark<br>
<br>
Then students have to give 3 reasons why it's the most effective way of doing
those tests. (3 marks)<br>
<br>
</i><br>
Hmm. What is "effective" about the order? It must relate to <b>how
well</b> it does the job of finding invalid numbers.<br>
<br>
But if <b>all 4 tests</b> are going to be conducted, any order of the 4 tests
will yield <b>exactly the same</b> results.<br>
<br>
It might be different if we wanted to find invalid numbers <b>soonest,</b> or
with the <b>minimum number of tests</b>, but they are <b>efficiency</b>
criteria, not effectiveness.<br>
<br>
I'm seriously starting to believe that this is a Bull Mastiff of a question...
All orders must be equally effective.<br>
<br>
I can usually work out what the examiners were <i>probably</i> trying to get
at, but this one has me completely baffled (like multichoice Q3 on the ITA
paper). <br>
I have no idea whatsoever of what knowledge the examiners are hoping I will
show.<br>
<br>
So, can anyone please tell me:<br>
<br>
1. how one order can be <i>more effective</i> than another.<br>
2. what order is most effective, and why the <i>reverse order</i> would be less
effective!<br>
<br>
Growl.<br>
<br>
Mark</span><o:p></o:p></p>
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