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<TITLE>Re: [Year 12 SofDev] SD Exam - Question 4</TITLE>
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<FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>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>
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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>
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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>
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Andrew<BR>
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-- <BR>
Andrew Shortell <BR>
(soon to leave Wallan SC)<BR>
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On 17/11/10 1:10 PM, "Mark KELLY" <<a href="kel@mckinnonsc.vic.edu.au">kel@mckinnonsc.vic.edu.au</a>> wrote:<BR>
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</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>Hi all. I've started getting a bee in my bonnet (or a terrier in my trousers) about Section C, Q4.<BR>
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<I>Percy is writing the program specification. For the section dealing with entry of the Medicare number he writes<BR>
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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>
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a. Place these validation tests in the most effective order. 1 mark<BR>
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Then students have to give 3 reasons why it's the most effective way of doing those tests. (3 marks)<BR>
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</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>
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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>
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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>
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I'm seriously starting to believe that this is a Bull Mastiff of a question... All orders must be equally effective.<BR>
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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>
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So, can anyone please tell me:<BR>
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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>
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Growl.<BR>
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Mark<BR>
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