First Normal Form (1NF)
The next step is to transform the table of unnormalised data into first normal form (1NF). The rule is: remove any repeating attributes to a new table. The process is as follows:
- Identify repeating attributes.
- Remove these repeating attributes to a new table together with a copy of the key from the UNF table.
- Assign a key to the new table (and underline it). The key from the original unnormalised table always becomes part of the key of the new table. A compound key is created. The value for this key must be unique for each entity occurrence.
1NF with repeating attributes removed
(You can also download this table as a PDF file.)
After removing the duplicate data the repeating attributes are easily identified.
In the previous table the Employee No, Employee Name, Department No, Department Name and Hourly Rate attributes are repeating. That is, there is potential for more than one occurrence of these attributes for each project code. These are the repeating attributes and have been to a new table together with a copy of the original key (ie Project Code).
A key of Project Code and Employee No has been defined for this new table. This combination is unique for each row in the table.
Next: Second Normal Form (2NF)