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<DIV><FONT face=Arial size=2>Hello all</FONT></DIV>
<DIV><FONT face=Arial size=2>just to chip in my 2-cents worth, yes, there might
be different processes that lead to a normalised db, but the definitions of 1NF,
2NF, and 3NF are pretty solid and have been for at least 30 years.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>attached is my version of the story</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards</FONT></DIV>
<DIV><FONT face=Arial size=2>Robert T-A</FONT></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=msc@luther.vic.edu.au href="mailto:msc@luther.vic.edu.au">Mark
Scott</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=itapps@edulists.com.au
href="mailto:itapps@edulists.com.au">Year 12 IT Applications Teachers' Mailing
List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, October 17, 2011 1:54
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Year 12 IT Apps] Normal
forms</DIV>
<DIV><BR></DIV>
<DIV class=WordSection1>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">Joseph<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">Your explanation looks and
sounds simple enough but...<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">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: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">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: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">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: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">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: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">thanks<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">Mark
Scott<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">Luther
College<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt">“Don’t water the rocks” Gerry
Smith, River Oaks Public School<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal style="MARGIN-LEFT: 36pt"><B><SPAN lang=EN-US
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">From:</SPAN></B><SPAN
lang=EN-US style="FONT-SIZE: 10pt; 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: 36pt"><o:p> </o:p></P>
<P class=MsoNormal
style="MARGIN-BOTTOM: 12pt; MARGIN-LEFT: 36pt; MARGIN-RIGHT: 0cm; mso-margin-top-alt: 0cm">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: 36pt">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: 36pt">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
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<P class=MsoNormal style="MARGIN-LEFT: 36pt"><o:p> </o:p></P></DIV>
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