[Year 12 IT Apps] Data Normalisation

[Robert Timmer-Arends]

Hello Benn

I'm not sure about your 2NF and 3NF because I'm not sure what 'cost', 'item cost' and 'item' are in relation to the original field 'item cost'.
However, as far as I can tell, except for one thing your first set of data is already in 1NF because no record has a repeating group; eg two book titles in the 'books purchased' field, or two equivalent fields such as 'books purchased 1' and 'books purchased 2'.

What is missing is a primary key that uniquely identifies each record. As far as I can tell this would mean the primary key should be: 'name' and 'book purchased'

In your 1NF you have split fields which, for this example, is probably a good idea, but not necessary to form 1NF; and you have added a 'cust id' field presumably as a primary key, but as pointed out above this will not uniquely identify a record, unless the intention is that 'cust id' is unique for each book purchased by each customer. I suspect that this is not intended so 'book' should also be italicised, indicating that it forms part of the primary key.

Once set up like this, one recognises that it is not in 2NF because there are fields that are dependent only on part of the primary key, thereby leading to the split tables as you have done.

Regards
Robert T-A


----- Original Message ----- 
  From: POLLOCK, Benn(POL) 
  To: itapps at edulists.com.au 
  Sent: Thursday, April 26, 2012 2:56 PM
  Subject: [Year 12 IT Apps] Data Normalisation


  Covering Data Normlisation at the moment. First time I've attempted this/taught this so I would appreciate any feedback you can give. I've attached an excel document with some Data that I gave to the students  to practice with, and I've just had a go at it myself - could someone tell me if It's correct? Going by everything I've read and other examples, it looks right to me but I could be wrong! Appreciate any feedback. 

   

  Benn Pollock

  Information Technology Teacher

  Wantirna College

  Ph: 9801 9700

   

   



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