[Informatics] ERD policy

Fri Apr 22 20:29:46 AEST 2016

Thanks Roger

I use this as an introduction .. the background noise is irritating but I like how she rattles it off 
https://www.evernote.com/l/AB_doASLxRlIZInCq6VIDRhUpfeOR0pAOoo <https://www.evernote.com/l/AB_doASLxRlIZInCq6VIDRhUpfeOR0pAOoo>

An opening handout that I issue
https://www.evernote.com/l/AB9sWC2XUGlDv4iFp6vMlBQ85r6FzAHRB9M <https://www.evernote.com/l/AB9sWC2XUGlDv4iFp6vMlBQ85r6FzAHRB9M>

And another that I adapted ..
https://www.evernote.com/l/AB9Kgf8CrE1EBIGvWU7yOYDrvq4mQ_h1UeU <https://www.evernote.com/l/AB9Kgf8CrE1EBIGvWU7yOYDrvq4mQ_h1UeU>

Hope that some find this helpful

Regards Roland

> On 18 Apr 2016, at 2:16 PM, Roger SIDHOM <rsidhom at ozford.edu.au <mailto:rsidhom at ozford.edu.au>> wrote:
> 
> I found this short Youtube video really helped!
>  
> https://www.youtube.com/watch?v=c0_9Y8QAstg <https://www.youtube.com/watch?v=c0_9Y8QAstg>
>  
> Roger Sidhom
>  
> From: ATKINSON-BUCK, Damien [mailto:Damien.ATKINSON-BUCK at ivanhoe.com.au <mailto:Damien.ATKINSON-BUCK at ivanhoe.com.au>] 
> Sent: Monday, 18 April 2016 12:36 PM
> To: Year 12 VCE Informatics Teachers' Mailing List
> Subject: Re: [Informatics] ERD policy
>  
> Hi Lucas, <>
> I think the N is a reference to the N used in mathematics when looking at the cardinality of sets of numbershttps://en.wikipedia.org/wiki/Cardinal_number <https://en.wikipedia.org/wiki/Cardinal_number> and https://en.wikipedia.org/wiki/Aleph_number <https://en.wikipedia.org/wiki/Aleph_number>
> Not sure when databases started using M as an additional letter to represent many, except to suggest that maybe it is was to avoid confusion of both tables requiring the same number of records by having the same letter linked to it?
> Cheers
> Damien
>  
>  
> Damien Atkinson-Buck  
> Head of Learning Area: Technology/Arts 
> <image001.png> <http:/>
> <image002.jpg> <http://www.ivanhoe.com.au/>	
> The Ridgeway, Ivanhoe VIC 3079 Australia
> p. +61 3 9490 3848
> e. damien.atkinson-buck at ivanhoe.com.au <mailto:damien.atkinson-buck at ivanhoe.com.au>
> w. www.ivanhoe.com.au <http://www.ivanhoe.com.au/>
> <image003.png> <http://www.facebook.com/IvanhoeGrammarSchool> <image004.png> <http://twitter.com/ivanhoegrammar>  
>  
> From: Garth, Lucas A [mailto:garth.lucas.a at edumail.vic.gov.au <mailto:garth.lucas.a at edumail.vic.gov.au>] 
> Sent: Monday, 18 April 2016 12:07 PM
> To: Year 12 VCE Informatics Teachers' Mailing List
> Subject: Re: [Informatics] ERD policy
>  
> Hi Natalie & Mark
>  
> Seems no one knows what is going on. I’ve drummed into my students that one to many is 1:N despite how illogical it looks.
>  
> I’d have been fine for one to many to be 1:M and many to many to have M:M or even M:N.  But the research books I’ve seen use 1:N.
>  
> I imagine N stands for “a number of records” rather than many records.  (Then why don’t we use N:N?)
>  
> In the end all we want is consistency and I’m not sure the document provides this.  Page 3 needs to change the top diagram to be 1:M to ensure all of the diagrams are consistent.
>  
> Maybe it’s best to just always use crows feet and be done with it.
>  
> Lucas
>  
>  
> From: informatics-bounces at edulists.com.au <mailto:informatics-bounces at edulists.com.au> [mailto:informatics-bounces at edulists.com.au <mailto:informatics-bounces at edulists.com.au>] On Behalf Of Heath, Natalie
> Sent: Monday, 18 April 2016 11:35 AM
> To: Year 12 VCE Informatics Teachers' Mailing List
> Subject: Re: [Informatics] ERD policy
>  
> Thanks Mark. I wish I’d had this when I was actually teaching it…. Last term….
>  
> Quick question. On page 3 the sample has 1:N library member borrows book…. Shouldn’t this be 1:M? Or am I missing something? 1:N isn’t in the list above it so I’m nicely confused.
>  
> Natalie
>  
> Mrs Natalie Heath
> ICT Learning Coordinator
>  
> <image005.jpg>
>  
> Marcellin College
> 160 Bulleen Road
> Bulleen VIC 3105 Australia
>  
> T +61 3 9851 1698
> ABN 77 413 001 496
>  
> marcellin.vic.edu.au <http://www.marcellin.vic.edu.au/>
> twitter.com/Marcellin <http://twitter.com/MCBulleen>
>  
> From: informatics-bounces at edulists.com.au <mailto:informatics-bounces at edulists.com.au> [mailto:informatics-bounces at edulists.com.au <mailto:informatics-bounces at edulists.com.au>] On Behalf Of Mark
> Sent: Monday, 18 April 2016 11:12 AM
> To: Year 12 VCE Informatics Teachers' Mailing List
> Subject: [Informatics] ERD policy
>  
> Hi folks. The long-awaited VCAA Entity Relationship Diagram policy <http://www.vcaa.vic.edu.au/Documents/vce/computing/Informatics_examination_ER_Conventions.docx> is out.
>  
> And it includes cardinality with both Chen "1/M/N" and crowsfeet notations!
>  
> Finally!
>  
> -- 
>  
> Mark Kelly
>  
> mark at vceit.com <mailto:mark at vceit.com>
> http://vceit.com <http://vceit.com/>
>  
> Natalie Heath
> Marcellin Staff
> 
> <image006.jpg>
> MARCELLIN COLLEGE
> 160 Bulleen Road
> Bulleen VIC 3105 Australia
> T +61 3 9851 1698
> F +61 3 9851 1555
> ABN 77 413 001 496 
> marcellin.vic.edu.au <http://marcellin.vic.edu.au/>
> twitter.com/Marcellin <http://twitter.com/Marcellin>
> DISCLAIMER: This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error, please notify the sender immediately by reply email and delete the email from your system. Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of Marcellin College. Marcellin College does not guarantee that this email is virus or error free and accepts no liability for any damage caused by any virus transmitted by this email.
> Important - This email and any attachments may be confidential. If received in error, please contact us and delete all copies. Before opening or using attachments check them for viruses and defects. Regardless of any loss, damage or consequence, whether caused by the negligence of the sender or not, resulting directly or indirectly from the use of any attached files our liability is limited to resupplying any affected attachments. Any representations or opinions expressed are those of the individual sender, and not necessarily those of the Department of Education and Training.
> 
> 
> 
> 
> 
> Privacy, Virus and Copyright Warning
> 
> The information contained in this electronic message (e-mail), and any files transmitted with it:
> 
> * is intended for the named recipients only. If you have received this in error, please advise the sender and delete it and any copies immediately;
> * Any personal information in this email must be used in accordance with the Privacy Act 1988 and this always applies even if it has been sent to you in error.
> * represents the views of the sender and does not necessarily represent the views or formal advice of Ivanhoe Grammar School;
> * may be subject to Copyright, so no further use should be made of it without the author's permission.
> 
> The School does not represent or warrant that the email or any files attached do not contain errors or are free from computer viruses or other defects nor does it accept responsibility for any loss or damage resulting directly or indirectly from the use of the email or any attached files. 
> _______________________________________________
> http://www.edulists.com.au <http://www.edulists.com.au/> - FAQ, resources, subscribe, unsubscribe
> VCE Informatics Mailing List kindly supported by
> http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html <http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html> - Victorian Curriculum and Assessment Authority <br>
> http://www.vitta.org.au <http://www.vitta.org.au/>  - VITTA Victorian Information Technology Teachers Association Inc <br>
> http://www.swinburne.edu.au/ict/schools <http://www.swinburne.edu.au/ict/schools> - Swinburne University

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.edulists.com.au/pipermail/informatics/attachments/20160422/579005c1/attachment-0001.html 