Relational Database and Normalization
Third Normal Form
The Third Normal Form rules:
- Requires the Second Normal Form.
- All attributes that do not belong to the primary key, but belong to another attribute, should be placed in a separate table.
There are moments when you want to append a new attribute in the table, but sometimes it will expand the table to an incredible size! And if the attributes are not tied to the main key - this is illogical!
Look at an example:
Here, Designer Grade and Designer Country are not Project's attributes. These attributes are tied to Designer only.
Let's normalize it!
Cool! Now we have two entities with separate tables:
- Project has only its attributes.
- Designer has only his attributes.
Results: Third Normal Form
|Improves the structure of the database|
|Takes up less memory|
What mean the Third Normal Form?
Select a few correct answers