Third Normal Form (3NF) in database normalization aims to remove transitive dependencies within tables. It ensures that each non-primary key attribute is dependent only on the primary key and not on other non-primary key attributes. Achieving 3NF involves breaking down tables to eliminate such dependencies.
For instance, consider a table named "Employee_Details" with columns: Employee_ID (Primary Key), Employee_Name, Department_ID, and Department_Name.
The objective of the Third Normal Form (3NF) is to eliminate transitive dependencies within a table. Let's illustrate the transformation of a table into 3NF by resolving such dependencies.
Consider a table named "Employee_Info" storing employee details such as Employee ID, Employee Name, Department ID, and Department Name.
Original Table: Employee_Info
Decomposition into 3NF:
Employee Information Table (3NF):
- The Employee Information Table contains unique employee details without transitive dependencies.
- The Department Table separates the Department ID and Department Name, ensuring each table represents distinct information and adheres to the Third Normal Form (3NF).
Additionally, let's consider further examples of tables in Third Normal Form (3NF) - "STUDENT," "COURSE," "PROFESSOR," and their mapping through "STUDENT_COURSE."
Additional Examples on Third Normal Form (3NF):
STUDENT Table (3NF):
COURSE Table (3NF):
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