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<DIV><FONT face=Arial size=2>Hello again Mark</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>what you say is true. I was talking about the
process of 'normalisation' (see Kevork's tute), not referential integrity.
If I understand your original email, the KK refers to 'integrity of data' not
'referential integrity'. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I agree that normalisation cannot eliminate the
possibilty of data losing its integrity (what's the opposite of integrity?), but
it goes a long way to prevent silly things that could occur in a non-normalised
db; eg imagine a db table containing teachers and their classes. Let's say there
is a teacher code, first name, second name and class name field. I currently
teach Maths and InfoTech so entries for me could be:</FONT></DIV>
<DIV><FONT face=Arial size=2>TIM, Robert, Timmer-Arends, Maths</FONT></DIV>
<DIV><FONT face=Arial size=2>TIM, Fred, Timmer-Arends, InfoTech</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>One person becomes two. </FONT><FONT face=Arial
size=2>Normalisation prevent this kind of thing by insisting that two tables be
created, one for names, the other for classes, with a relationship between the
two</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>(sorry if I'm stating the obvious)</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>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>----- Original Message ----- </DIV>
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<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=kel@mckinnonsc.vic.edu.au
href="mailto:kel@mckinnonsc.vic.edu.au">Mark KELLY</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> Saturday, March 27, 2010 12:38
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Year 12 IT Apps] ITA new
design. Sorry - another one.</DIV>
<DIV><BR></DIV>Hi Robert. MS Access has the 'enforce referential
integrity' tickbox (or so I am led to believe) so RI is <I>somewhat</I>
related to software implementation.<BR><BR>And it can't be solely a database
<I>design </I>issue. <BR><BR>Setting up 2 related tables - even with a
perfect design - will not prevent accidental entry of a value which fails to
find a match in a foreign key field. <BR><BR>RI, however, <I>does</I>
detect data entries for which there is no foreign key field match and
prevents/challenges their entry.<BR><BR>2.2 cents' worth.<BR><BR>
<DIV class=gmail_quote>On Fri, Mar 26, 2010 at 4:07 PM, Timmer-Arends <SPAN
dir=ltr><<A
href="mailto:timmer@melbpc.org.au">timmer@melbpc.org.au</A>></SPAN>
wrote:<BR>
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<DIV bgcolor="#ffffff">
<DIV><FONT face=Arial size=2>Hello Mark</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>'normalisation' refers to a process of database
table design that eliminates 'flaws' in a design that could lead to data
integrity problems. It is a software independent process.</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>
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<DIV>
<DIV></DIV>
<DIV class=h5>
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV style="BACKGROUND: rgb(228,228,228); FONT: 10pt arial"><B>From:</B>
<A title=kel@mckinnonsc.vic.edu.au href="mailto:kel@mckinnonsc.vic.edu.au"
target=_blank>Mark KELLY</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=itapps@edulists.com.au
href="mailto:itapps@edulists.com.au" target=_blank>Year 12 IT Applications
Teachers' Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, March 26, 2010 3:02
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Year 12 IT Apps] ITA new
design. Sorry - another one.</DIV>
<DIV><BR></DIV>Apologies for all the posts, but the new design is an
interesting beast.<BR><BR>ITA U3O2 Key Knowledge 11 - <B>"ways in which
normalisation can ensure the integrity of data in an
RDBMS"</B><BR><BR>Assuming they mean "referential integrity", this will be
an interesting dotpoint if you're using Filemaker which does not use the
concept of referential integrity*<BR><BR><BR>*Except as an awkward kludge
by using a validation rule ("exists in limited list") and defining the
list to include values in a foreign key field.<BR clear=all><BR>--
<BR>Mark Kelly<BR>Manager - Information Systems<BR>McKinnon Secondary
College<BR>McKinnon Rd McKinnon 3204, Victoria, Australia<BR>Direct line /
Voicemail: 8520 9085<BR>School Phone +613 8520 9000<BR>School Fax +613
9578 9253<BR><A href="mailto:kel@mckinnonsc.vic.edu.au"
target=_blank>kel@mckinnonsc.vic.edu.au</A><BR><BR>Webmaster - <A
href="http://www.mckinnonsc.vic.edu.au"
target=_blank>http://www.mckinnonsc.vic.edu.au</A><BR>IT Lecture notes: <A
href="http://vceit.com" target=_blank>http://vceit.com</A><BR>Moderator:
IT Applications Mailing List<BR><BR><BR></DIV></DIV>
<DIV class=im>_______________________________________________ <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/infotechindex.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</DIV></BLOCKQUOTE>
<DIV class=im>_______________________________________________ <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/infotechindex.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</DIV></DIV></BLOCKQUOTE></DIV><BR><BR clear=all><BR>-- <BR>Mark
Kelly<BR>Manager - Information Systems<BR>McKinnon Secondary
College<BR>McKinnon Rd McKinnon 3204, Victoria, Australia<BR>Direct line /
Voicemail: 8520 9085<BR>School Phone +613 8520 9000<BR>School Fax +613 9578
9253<BR><A
href="mailto:kel@mckinnonsc.vic.edu.au">kel@mckinnonsc.vic.edu.au</A><BR><BR>Webmaster
- <A
href="http://www.mckinnonsc.vic.edu.au">http://www.mckinnonsc.vic.edu.au</A><BR>IT
Lecture notes: <A href="http://vceit.com">http://vceit.com</A><BR>Moderator:
IT Applications Mailing
List<BR><BR><BR>_______________________________________________ <BR><A
href="http://www.edulists.com.au">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 ">http://www.vcaa.vic.edu.au/vce/studies/infotech/infotechindex.html
</A>- Victorian Curriculum and Assessment Authority and <BR><A
href="http://www.vitta.org.au">http://www.vitta.org.au </A>- VITTA Victorian
Information Technology Teachers Association Inc</BLOCKQUOTE></BODY></HTML>