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</o:shapelayout></xml><![endif]--></head><body lang=EN-AU link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt'>Joseph<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>Your explanation looks and sounds simple enough but...<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>There are at least half a dozen different definitions of this process. (although the 1NF explanation is fairly consistent) <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>And, most importantly, we still do not know how the VCAA (Hi Paula) defines the process of Normalisation and in particular the first three forms.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>I’m expecting a very simple question on this on the exam (hopefully just a 1NF question).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>Anything too complicated and this mailing list will be on fire after the exam.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>thanks<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>Mark Scott<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>Luther College<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>“Don’t water the rocks” Gerry Smith, River Oaks Public School<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:36.0pt'><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"'> itapps-bounces@edulists.com.au [mailto:itapps-bounces@edulists.com.au] <b>On Behalf Of </b>Joseph Papaleo<br><b>Sent:</b> Monday, 17 October 2011 1:36 PM<br><b>To:</b> Year 12 IT Applications Teachers' Mailing List<br><b>Subject:</b> Re: [Year 12 IT Apps] Normal forms<o:p></o:p></span></p><p class=MsoNormal style='margin-left:36.0pt'><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt'>Mark,<br>In a nutshell, I've taught it as :<br><br>1NF - tidy the table(s) up horizontally<br>ie Fields contain only a single value eg Name: Mr Barney Rubble changes to <br>Title: Mr<br>Fname: Barney <br>Sname: Rubble<br clear=all><br>Remove repeating Groups (as per Mark's comments)<br><br><br>2NF - Tidy the table(s) up Vertically<br>Eliminate duplication in records down the table by using a Primary Key that each record refers to.<br>Continue to do this as often as required until duplication is removed from all tables- students should see the need for a new table if there is duplication with their own unique Primary Key.<br><br><br>3NF - Make all fields in a table Mutually Exclusive<br>ie, no field can rely on another. eg table may contain "Quantity" and "Price", but it cannot contain "Total Cost" as Total cost = Quantity x Price.<br><br>I'm concerned that my students understand this, but they found it difficult to do. Also concerned that I may have used an old or inferior resource.<br><br><br><br><br>Joseph Papaleo<br>Ivanhoe Grammar School,<br>Plenty Campus<br><br><br><br><o:p></o:p></p><div><p class=MsoNormal style='margin-left:36.0pt'>On Mon, Oct 17, 2011 at 1:04 PM, Mark KELLY <<a href="mailto:kel@mckinnonsc.vic.edu.au">kel@mckinnonsc.vic.edu.au</a>> wrote:<o:p></o:p></p><p class=MsoNormal style='margin-left:36.0pt'>Groan. I just spent another 30 minutes trying to explain the differences between 2NF and 3NF to my dears. <br>As usual, by the time I finished, I think they knew less than when I started.<br><br>1NF is pretty clear cut...<br> - no duplicate rows (i.e. identical records)<br> - no multiple columns that contain the same *type* of data (e.g. child1, child2, child3)<br> - only one piece of data per field (e.g. don't store 2 phone numbers for a person in the 'phone' field; put street address/suburb/postcode in separate fields; in Filemaker, don't use repeating fields) <br><br>But 2NF is really only a problem if you use *multiple* fields as a key (e.g. using firstname + lastname + phone as a unique key) instead of using a unique and arbitrary key field, like an ID number. <br>I realise now that my kids have trouble absorbing 2NF because at no time in their database education have I ever *mentioned* the possibility of using multiple fields as the key. So explaining 2NF to them was a bit like warning them not to walk using their ears - the concept had never even dawned on them before. To them, having a non-key field that did not give information about *all* of the key fields was a strange and scary possibility.<br><br>3NF is, I think, relatively straight forward. Each non-key field must give information about the key and not to another non-key field. Violation of 3NF is usually pretty obvious because it looks "strange".<br><br>After 2 slideshows, I'm still trying to work out a way to make it sound really clear... next time, maybe. If anyone has hit on a sure-fire summary of differentiating normal forms, I'd love to hear of it.<br><br>Regards<br><span style='color:#888888'><br>-- <br>Mark Kelly<br>Manager of ICT, Reporting, IT Learning Area<br>McKinnon Secondary College<br>McKinnon Rd McKinnon 3204, Victoria, Australia<br>Direct line / Voicemail: <a href="tel:%2B613%208520%209085" target="_blank">+613 8520 9085</a>, Fax <a href="tel:%2B613%209578%209253" target="_blank">+613 9578 9253</a><br><a href="mailto:kel@mckinnonsc.vic.edu.au" target="_blank">kel@mckinnonsc.vic.edu.au</a><br>VCE IT Lecture Notes: <a href="http://vceit.com" target="_blank">http://vceit.com</a><br>Moderator: <a href="http://www.edulists.com.au/" target="_blank">IT Applications Edulist</a><br><br>Want a good time? Call 0112358. Ask for Mr Fibonacci.<br></span><br>_______________________________________________<br><a href="http://www.edulists.com.au" target="_blank">http://www.edulists.com.au</a> - FAQ, resources, subscribe, unsubscribe<br>IT Applications Mailing List kindly supported by<br><a href="http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html" target="_blank">http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html</a> - Victorian Curriculum and Assessment Authority and<br><a href="http://www.vitta.org.au" target="_blank">http://www.vitta.org.au</a> - VITTA Victorian Information Technology Teachers Association Inc<o:p></o:p></p></div><p class=MsoNormal style='margin-left:36.0pt'><o:p> </o:p></p></div></body></html>