Normalisation in a Video Library

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Stephen Mathieson

NORMALISATION

A video library operates in a similar way to any normal library, so the first thing to do is to write down a list of attributes for the whole of the system. It would in this case be easy to put the attributes straight into separate tables but in a more complex system this would not do.  It is also important not to list to many attributes, only keeping it to the ones that are definitely needed.

MEMBER (Membership number, Surname, Forename, Title, Street, Town, Postcode, Date of birth, Tel. No., (Video number, Video title, Category, Cost, Price, Rental price, Date borrowed))

At this stage I have placed all the attributes into the entity MEMBER. I must now go through the normalisation process to determine how many tables are needed and which ones they will be.

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Due to the video details being repeating attributes they need to be removed and put into 1NF by being giving their own entity.

 MEMBER (Membership number, Surname, Forename, Title, Street, Town, Postcode, Date of birth, Tel. No.,)

Membership Number is underlined because in this case it is a key field, all the other attributes relate to this field.

VIDEO RENTAL  (Membership number, Video number, Video title, Category, Cost, Price, Rental price, Date borrowed)

The data now needs converted to 2NF.  This needs to be done because the attributes do not depend on both keys.  Video ...

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