Difference between revisions of "Database Normalisation"
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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. | 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 | + | To use Normalisation to create a Relational Database you need to start with the data in one large (un-normalised) table. |
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| + | ==Step 1== | ||
Remove repeating groups to give 1NF | Remove repeating groups to give 1NF | ||
| + | ==Step 2== | ||
Remove partial dependencies to give 2NF | Remove partial dependencies to give 2NF | ||
| + | ==Step 3== | ||
Remove non-key dependencies to give 3NF | Remove non-key dependencies to give 3NF | ||
| + | ==The Outcome== | ||
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 10:47, 21 May 2017
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 you need to start with the data in one large (un-normalised) table.
Contents
Step 1
Remove repeating groups to give 1NF
Step 2
Remove partial dependencies to give 2NF
Step 3
Remove non-key dependencies to give 3NF
The Outcome
The final normalized table will have no repeating groups and will have all the tables in the database linked via common keys.
