[Year 12 IT Apps] Table Normalisation
Robert Hind
robert at yinnar.com
Thu Mar 31 15:09:03 EST 2011
Hi Mark,
Nothing so interesting as discussing NF1-3, more a Panadeine Forte and a bottle of red I would have thought :-) The article I suggested was the "least confusing" of several found. There does however seem to be perhaps a need for the VCAA to spell out a bit more clearly its meanings of NF1-3 as there do seem to be several different versions around.
If you want a really clear explanation :-( then try http://dev.mysql.com/tech-resources/articles/intro-to-normalization.html#03
I would be interested to know the origin of Laura's sample question. And just what they did expect as an answer for two marks. Also how can you apply just one of NF1, NF2 or NF3 to a table when each one assumes the previous requirements have been satisfied?
Where do we go?
1NF: Two new fields in the database table so that the "Street Address" and "Suburb" become separate fields and "Family_Name" and "Given_Name" also become separate fields - atomicity, no more than one value in a field
2NF: Dividing the data into at least two tables: eg perhaps Member_Details: Primary key, Member names, Address details, Gender (? is gender needed, if not is it allowed under present laws?), Membership type
and Membership_Types: Primary key, Membership fee, Boat storage fee
and establishing the relationships between the tables
3NF: ? Perhaps nothing more.
Robert Hind (Semi-retired) OOF, GOM
Ashwood and Traralgon
robert at yinnar.com
----- Original Message -----
From: Mark KELLY
To: Year 12 IT Applications Teachers' Mailing List
Sent: Thursday, March 31, 2011 2:28 PM
Subject: Re: [Year 12 IT Apps] Table Normalisation
I looked up normalisation levels 1-3 and had to have a Bex and a good lie down.
It's funny because normally I love discussing things like how NF2 aims to ensure that no non-prime attribute in the table is functionally dependent on a proper subset of a candidate key.
:-o
On 31 March 2011 13:02, Robert Hind <robert at yinnar.com> wrote:
You might like to look at
http://databases.about.com/od/specificproducts/a/normalization.htm
Robert Hind (Semi-retired) OOF, GOM
Ashwood and Traralgon
robert at yinnar.com
----- Original Message -----
From: Laura Fihelly
To: Year 12 IT Applications Teachers' Mailing List
Sent: Thursday, March 31, 2011 10:59 AM
Subject: [Year 12 IT Apps] Table Normalisation
Hi everyone,
Can someone please help me with this Sample Exam question. I am trying to understand table normalization. I have a general understanding of what it means, but I’m not really sure about the actual differences in this particular question between the second and third normal forms. As a class we have been going through the textbook definition, but I’m struggling to apply it to this particular sample question.
Also if anyone has some good resources on a simple (not so technical way) of how to explain this easier it would be greatly appreciated.
Thanks
Question 1
Below is a table from a yacht club’s relational database.
Name
Boat Name
Address_Suburb
State
memType
Fees $
Gender
Boat Storage Fees $
Total Fees Due $
Sue Trowsdale
Suzy
21 Mountain Rd Rosebud
VIC
Senior
250.00
F
125.00
375.00
Jon Ross
Wahoo
64 View Rd McCrae
VIC
Junior
140.00
M
–
140.00
Harry Wilson
Victor
35 Shady Ln Rosebud
VIC
Life
–
M
125.00
125.00
2 marks
a. Describe what would happen when you apply one of the First, Second or Third Normal Forms to data in the table. Refer to the table in your answer.
Tick the box to indicate which normal form you are describing.
First o or Second o or Third o
____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
____________________________________________________________________________________
Laura Fihelly
Teacher of Business Management & Information Technologies
Catholic Regional College Sydenham
380 Sydenham Road
Sydenham 3037
email: fihl at crcsydenham.net
web: www.crcsydenham.net
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Mark Kelly
Manager of ICT, Reporting, IT Learning Area
McKinnon Secondary College
McKinnon Rd McKinnon 3204, Victoria, Australia
Direct line / Voicemail: +613 8520 9085, Fax +613 9578 9253
kel at mckinnonsc.vic.edu.au
VCE IT Lecture Notes: http://vceit.com
Moderator: IT Applications Edulist
All generalisations are false, except this one.
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