In third normal form, the tables must satisfy the second normal form and should additionally satisfy the condition that all non-primary key columns must be directly dependent on the entire primary key and must be independent of each other.
Think about the Country column for a moment. Given the Latitude and Longitude, you can easily derive the Country column. Even though the country where a superpower was sighted is dependent on the Name-Power composite primary key, it is only indirectly dependent on them.
So, let's separate the location details into a separate countries table as follows:
|
Location ID |
Latitude* |
Longitude* |
Country |
|
1 |
+40.75170 |
-73.99420 |
USA |
|
2 |
+35.68330 |
+139.73330 |
Japan |
