[Year 12 IT Apps] Database relationships
Jim Maunder
techo at ruyton.vic.edu.au
Fri Jul 25 12:01:19 EST 2008
Hi Mark -
I don't mind at all - the info is in my sig, and repeated here.
I watch (and sometimes post to) these lists for
my own techo interests, and to pass on useful
info to our teachers. One of the pieces in my
chequered past was working as a programmer at
Monash Uni doing clever things with VCE results
and course choices using CA Clipper and MS
Access. I also have some expertise with DEC
Datatrieve (which got me a contract at Scotch
doing their end of year processing, including the
end of year student reports (pre-Markbook thank
goodness)), so that brands me as a really old frat (sp?)!
rgds
Jim
Jim Maunder
Laptop and PC Support Technician
Ruyton Girls School
Melbourne, Australia
ph 03 9290 9374
At 10:59 AM 25/07/2008, you wrote:
>Hi Jim. If you're not a teacher, would you mind
>saying where you are/what you do/why you're here?
>
>Relationships are great fun, and source of
>endless debate amongst people. I think database
>structures border on works of creative art, sometimes.
>
>It's a sad sign that I sometimes lie awake at
>night pondering complex relationships that involve key fields instead of women
>
>:-(
>
>
>Jim Maunder wrote:
>>Don't know if this will help:
>>I'm not even a teacher let alone an IPM teacher
>>- but I have fiddled with databases in my
>>chequered past and remember something about 3rd
>>normal form from the Grad Dip Comp course 20
>>odd years ago. I set up a quick sample in
>>Access to show how I would go about a student database:
>>Emacs!
>>I would say that students and form have a 1 to
>>1 relationship, and that students and stud_subj
>>has a 1 to many relationship, but I'm only guessing.
>>rgds
>>Jim
>>
>>At 05:25 PM 24/07/2008, you wrote:
>>>Yes it is confusing but I would still argue
>>>that it is one entity and that entity has a
>>>number of data relationships in it. There is
>>>also only one Medicare card number on it and
>>>that is unique each child does not get their
>>>own Medicare card with a different Medicare number.
>>>
>>>
>>>
>>>
>>>Kind regards
>>>
>>>Allan Barnes, CEO
>>>Australian Institute of Education and Training
>>>P.O. Box 171
>>>Brunswick West 3055
>>>Ph: (03) 9387 2051
>>>FAX: (03) 9387 3470
>>>Mobile: 0409 428 221
>>>
>>>
>>>*From:* itapps-bounces at edulists.com.au [
>>>mailto:itapps-bounces at edulists.com.au] *On Behalf Of *Russo, Frank R
>>>*Sent:* Thursday, 24 July 2008 8:33 AM
>>>*To:* Year 12 IT Applications Teachers' Mailing List
>>>*Subject:* RE: [Year 12 IT Apps] Database relationships
>>>
>>>Sorry but a medicare card can have multiple
>>>members in it but each member can have their own card !!!
>>>
>>>Now that’s confusing
..
>>>
>>>Frank Russo
>>>ICT ~ Teaching & Learning
>>>Monterey Secondary College
>>>------------------------------------------------------------------------
>>>*From:* itapps-bounces at edulists.com.au [
>>>mailto:itapps-bounces at edulists.com.au] *On Behalf Of *Allan Barnes
>>>*Sent:* Wednesday, 23 July 2008 9:14 PM
>>>*To:* 'Year 12 IT Applications Teachers' Mailing List'
>>>*Subject:* RE: [Year 12 IT Apps] Database relationships
>>>
>>>An example of a one-to-one relationship would
>>>be something like a ‘person’ entity and a
>>>‘medicare card’ entity one person can only
>>>have one medicare card, and one medicare card can only belong to one person.
>>>
>>>
>>>
>>>
>>>
>>>Kind regards
>>>
>>>Allan Barnes, CEO
>>>Australian Institute of Education and Training
>>>P.O. Box 171
>>>Brunswick West 3055
>>>Ph: (03) 9387 2051
>>>FAX: (03) 9387 3470
>>>Mobile: 0409 428 221
>>>*From:* itapps-bounces at edulists.com.au [
>>>mailto:itapps-bounces at edulists.com.au] *On Behalf Of *Mia Alexiou
>>>*Sent:* Wednesday, 23 July 2008 9:05 PM
>>>*To:* Year 12 IT Applications Teachers' Mailing List
>>>*Subject:* Re: [Year 12 IT Apps] Database relationships
>>>
>>>Hi all,
>>>
>>>I'm an intruder here (I tech year 11 not year
>>>12) but I thought I could share my somewhat rusty knowledge of databases.
>>>
>>>In response to Lisa's question the
>>>employee/department relationship is
>>>one-to-many. As for "true" one-to-one
>>>relationships I've never seen one in action
>>>and so doubt they are common at a small database level.
>>>That being said, I can think of a couple of
>>>situations where they might be useful such as
>>>splitting commonly needed data from that which
>>>is rarely needed, to reduce the time it takes
>>>to run queries over a huge table. Another
>>>reason might be security, with highly
>>>sensitive data being stored in a separate table.
>>>
>>>A 0 or 1 to-many relationship is much more
>>>common and is what most people (even in
>>>industry) usually mean when they talk about
>>>one-to-one relationships. These are explained
>>>nicely (under the one-to-one heading!) at
>>>http://www.onlamp.com/pub/a/onlamp/2001/03/20/aboutSQL.html.
>>>
>>>I hope this was helpful
>>>
>>>Mia Alexiou
>>>RMIT TAFE
>>>Information Technology
>>>Sessional Teacher
>>>On Wed, Jul 23, 2008 at 6:10 PM, Lisa Imms
>>><lisimms at copticvic.org <mailto:lisimms at copticvic.org>> wrote:
>>>Hi Mark,
>>>
>>>Firstly, thanks for the resource :-)
>>>
>>>I hate to even contemplate disagreeing with
>>>you as my ITA class and I regard you as the
>>>ITA font-of-all-knowledge, but I will try this anyway.....
>>>
>>>Your example for one-to-one: "E.g. an
>>>employee's department data in one table
>>>matches a corresponding department in another
>>>table, allowing data relating to that department to be fetched."
>>>
>>>Wouldn't this be a one to many relationship?
>>>Even the line you have joining them has the
>>>'many feathers' at the employees table?
>>>Although each employee can belong to only one
>>>department, each department can (and will)
>>>have multiple employees? So it is actually a one to many relationship?
>>>
>>>Am I correct in assuming that a well organised
>>>database would not have any one-to-one
>>>relationships? The two tables in a one-to-one
>>>relationship could/should just be merged into one table?
>>>
>>>Lisa Bairstow
>>>St Mary's Coptic Orthodox College
>>>
>>>________________________________
>>>
>>>From: itapps-bounces at edulists.com.au
>>><mailto:itapps-bounces at edulists.com.au> on behalf of Mark Kelly
>>>Sent: Wed 7/23/2008 2:24 PM
>>>To: Year 12 IT Applications Teachers' Mailing List
>>>Subject: [Year 12 IT Apps] Database relationships
>>>
>>>
>>>
>>>Hi all. It's been mighty quiet here for a while. To perk things up,
>>>here's a little revision for database relationships (1-1, 1-many,
>>>many-many) that may or may not be useful.
>>>
>>>Cheers
>>>Mark
>>>
>>>--
>>>Mark Kelly
>>>Manager - Information Systems
>>>McKinnon Secondary College
>>>McKinnon Rd McKinnon 3204, Victoria, Australia
>>>Direct line / Voicemail: 8520 9085
>>>School Phone +613 8520 9000
>>>School Fax +613 95789253
>>>kel AT mckinnonsc.vic.edu.au <http://mckinnonsc.vic.edu.au>
>>>Webmaster - http://www.mckinnonsc.vic.edu.au <
>>>http://www.mckinnonsc.vic.edu.au/>
>>>IT Lecture notes: http://vceit.com <http://vceit.com/ >
>>>Moderator: IT Applications Mailing List
>>>
>>>If you Declare War - is it integer or boolean?
>>>_______________________________________________
>>>http://www.edulists.com.au <
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>>>IT Applications Mailing List kindly supported by
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>>>Information Technology Teachers Association Inc
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>>>IT Applications Mailing List kindly supported by
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>>>Information Technology Teachers Association Inc
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>>>_______________________________________________
>>>http://www.edulists.com.au
>>><http://www.edulists.com.au>- FAQ, resources, subscribe, unsubscribe
>>>IT Applications Mailing List kindly supported by
>>>http://www.vcaa.vic.edu.au/vce/studies/infotech/infotechindex.html
>>><http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html%20>-
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>>>http://www.vitta.org.au
>>><http://www.vitta.org.au>- VITTA Victorian
>>>Information Technology Teachers Association Inc
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>>>IT Applications Mailing List kindly supported by
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>>><http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html%20>-
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>>>http://www.edulists.com.au
>>><http://www.edulists.com.au>- FAQ, resources, subscribe, unsubscribe
>>>IT Applications Mailing List kindly supported by
>>>http://www.vcaa.vic.edu.au/vce/studies/infotech/infotechindex.html
>>><http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html>-
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>>><http://www.vitta.org.au>- VITTA Victorian
>>>Information Technology Teachers Association Inc
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>>Views, opinions, etc. expressed reflect those of the author and not
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>>-----------------------------------------------------------
>>Jim Maunder
>>Laptop and PC Support Technician
>>Ruyton Girls School
>>Melbourne, Australia
>>ph 03 9290 9374
>>_______________________________________________
>>http://www.edulists.com.au
>><http://www.edulists.com.au> - FAQ, resources, subscribe, unsubscribe
>>IT Applications Mailing List kindly supported by
>>http://www.vcaa.vic.edu.au/vce/studies/infotech/infotechindex.html
>><http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html
>> > - Victorian Curriculum and Assessment Authority and
>>http://www.vitta.org.au
>><http://www.vitta.org.au> - VITTA Victorian
>>Information Technology Teachers Association Inc
>
>
>--
>Mark Kelly
>Manager - Information Systems
>McKinnon Secondary College
>McKinnon Rd McKinnon 3204, Victoria, Australia
>Direct line / Voicemail: 8520 9085
>School Phone +613 8520 9000
>School Fax +613 95789253
>kel AT mckinnonsc.vic.edu.au
>
>Webmaster - http://www.mckinnonsc.vic.edu.au
>IT Lecture notes: http://vceit.com
>Moderator: IT Applications Mailing List
>
>A conclusion is the place where you got sick of thinking.
>If you Declare War - is it integer or boolean?
>
>_______________________________________________
>http://www.edulists.com.au - FAQ, resources, subscribe, unsubscribe
>IT Applications Mailing List kindly supported by
>http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html
>- Victorian Curriculum and Assessment Authority and
>http://www.vitta.org.au - VITTA Victorian
>Information Technology Teachers Association Inc
>
>
>No virus found in this incoming message.
>Checked by AVG - http://www.avg.com Version:
>8.0.138 / Virus Database: 270.5.5/1571 - Release Date: 7/24/2008 5:42 PM
>
-----------------------------------------------------------
We have to use this Disclaimer
Views, opinions, etc. expressed reflect those of the author and not
Ruyton Girls' School
-----------------------------------------------------------
Jim Maunder
Laptop and PC Support Technician
Ruyton Girls School
Melbourne, Australia
ph 03 9290 9374
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