# Er diagrams and Normalisation



## bush (Aug 26, 2003)

Anyone here know anything about normalisation, codds law and third normal form?

Really need some help on a small problem


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## Gibble (Oct 10, 2001)

Sure fire away, I know that stuff...but this should be moved over to development (I'll have a mod move the thread)


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## bush (Aug 26, 2003)

Thanks sorry for posting in the wrong place, wasnt sure where to put it. Anyway i have an assignment for college and i have it all done except this small question. The teahcher wasnt very good at explaining it and im finding it hard with the notes she gave. Its probably simple

Is the following entity in third normal form? If not put into third normal form and explain each step

Bank Account no. (underlined)
Bank Sort Code (underlined)
Customers name
Customers address
Type of account
Customers contact no.
Bank address
Bank manager

Let me know what you think


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## Gibble (Oct 10, 2001)

Oh god, that's not even close to 3NF.

To get too 3NF you must split this up into distinct tables where each item refers only to that tables primary, there is no duplication of data in the tables, and each table must have it's own primary key.

eg, 
Customer information should be in it's own table, with a unique customerID.
Bank information should be in it's own table with a unique bankID
Account information should be in it's own table with a unique accountID.
Names should be broken into First/Last/Middle(initial) (names can be a unique table since a manager can be a customer as well..but both are people (perhaps a person table...)
Addresses span multiple fields (num/street/city/prov/country...) and addresses can be a unique table

You'll need tables that tie all the information together...

This is far from a small question.


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## bush (Aug 26, 2003)

Its only worth 8 marks out of 100 so i presumed it was a small question. I dont think i need to go into as much detail as you are saying , eg Names should be broken into First/Last/Middle(initial). I think we just do simplified versions wrote down on paper

Heres the full question

Is the following entity in third normal form? If not put it into third normal form and explain each step. Note. Each bank has its own unique bank code and each customer within the bank will have at least one bank account. You can assume each bank account associated with only one customer.

Bank Account no. (underlined)
Bank Sort Code (underlined)
Customers name
Customers address
Type of account
Customers contact no.
Bank address
Bank manager


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## Gibble (Oct 10, 2001)

Well, I'm not going to do the question for you...you won't learn that way...

Make an attempt at it, and lets see what you come up with, and I'll help from there.


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## bush (Aug 26, 2003)

Thats the thing ive absolutley no idea how to do it, its the only thing i dont know and ill never need to know it ever again and i dont really have time to learn it at this stage anyway
Thanks for the help anyway


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## Rockn (Jul 29, 2001)

If you are doing any database design you will absolutely use normalization on a regular basis. Learn it, know it, live it. Try some HIPPA database normalization once to conform to their standads.


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## Gibble (Oct 10, 2001)

bush said:


> Thats the thing ive absolutley no idea how to do it, its the only thing i dont know and ill never need to know it ever again and i dont really have time to learn it at this stage anyway
> Thanks for the help anyway


Trust me, if you do any programming you WILL need to know this, any DBA, Programmer, etc will need to know this at some point.


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## bush (Aug 26, 2003)

Im changing course after this year though and i wont need it, i just need to pass this course first


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## Gibble (Oct 10, 2001)

well, you're going to have to learn it if you want to get through the exam...we're trying to help.

Do what you can, and we'll help you from there, but if you don't make any effort, why should we?


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## bush (Aug 26, 2003)

I have been making an effort ive been studying this stuff that i hate for the last week. I havent got time to do anymore

Its ok ill do without it :up:


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## Gibble (Oct 10, 2001)

What is it you are planning on becoming?


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## bush (Aug 26, 2003)

A man


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## Rockn (Jul 29, 2001)

LMAO....a man!! Why are you changing course? Are you gonna be one of the people that take 8 years to get a bachelors degree?


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## bush (Aug 26, 2003)

Ha Ha ye probably


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