Difference between revisions of "Database Normalisation"
ThomasWard (talk | contribs) (Created page with "An un-normalised database is a database that has not undergone the process to remove unnecessary or repeating information from the system's tables. Normalisation will remove t...") |
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Start with the data in one large (un-normalised) table | Start with the data in one large (un-normalised) table | ||
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Remove repeating groups to give 1NF | Remove repeating groups to give 1NF | ||
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Remove partial dependencies to give 2NF | Remove partial dependencies to give 2NF | ||
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Remove non-key dependencies to give 3NF | Remove non-key dependencies to give 3NF | ||
The final normalized table will have no repeating groups and will have all the tables in the database linked via common keys. | The final normalized table will have no repeating groups and will have all the tables in the database linked via common keys. | ||
Revision as of 14:58, 22 December 2016
An un-normalised database is a database that has not undergone the process to remove unnecessary or repeating information from the system's tables. Normalisation will remove this data providing a more efficient database requiring less storage.
To use Normalisation to create a Relational Database we do the following:
Start with the data in one large (un-normalised) table
Remove repeating groups to give 1NF
Remove partial dependencies to give 2NF
Remove non-key dependencies to give 3NF
The final normalized table will have no repeating groups and will have all the tables in the database linked via common keys.
