Third Normal Form (3NF)
This normal form speaks about transitive dependency.
A database relation (a database table) is said to meet third normal form standards if all the attributes (database columns) are functionally dependent on solely the primary key.That is 3NF is a relation in second normal form where all non-prime attributes depend only on the candidate keys and do not have a transitive dependency on another key. This says that we should remove transitive dependency if they are exist. What is transitive dependency?
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It is a condition such as in
Student relation, StudentCode determines the Town (StudentCode→Town) and Town determines the Province (Town→Province), therefore StudentCode determines Province (Note that, as per this relation StudentCode detemines Province but the issue is it can be determined by Town too).
A determines B (A→B) and B determines C (B→C), then A determines C (A→C).
For removing transitive dependency, we need to decompose the relation.
