NORMALISATION

Fiona Faulkner
Mind Map by , created over 6 years ago

A level A Level ICT Mind Map on NORMALISATION, created by Fiona Faulkner on 05/14/2013.

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Fiona Faulkner
Created by Fiona Faulkner over 6 years ago
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NORMALISATION
1 1NF
1.1 All data is atomic
1.2 Has a PK
1.3 No repeating data/fields
1.4 unique field names
2 2NF
2.1 Already in 1NF
2.2 All non-key fields are dependent on the whole PK
2.2.1 all field data can be found by looking at entire PK
3 3NF
3.1 table is already in 2NF
3.2 No functional dependency between non-key fields
4 ADVANTAGES
4.1 increased data integrity - only 1 copy so correct
4.2 flexibility for expanding database in future
4.3 easier to maintain database
4.4 less storage space needed, so smaller hard drive
5 DISADVANTAGES
5.1 reduces database performance - more tables=slower processing
5.2 results of historial calculations can't be stored
5.3 may not meet needs of comapny, e.g. store address as 1 field

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