Database Normalization

Normalization

• process of organizing a database to reduce redundancy problem and improve data integrity

Functional Dependency

• 하나의 atrribute가 다른 attribute의 value를 결정하는지 여부를 판단
• well formed인지 판별할 수 있는 기준
• A(Determinant) -> B(dependent): A가 결정되면 B도 결정된다면 B는 A에 함수적 종속
• Every determinant must be a Candidate Key

Normalization Process

• BCFNF: Boyce-Codd Normal Form => Each relation has only one theme

1. Identify all the Candidate Keys.
2. Identify all the Functional Dependencies.
3. Examine the determinants of the functional dependencies
   1. place the columns of the functional dependency in a new relation of their own
   2. make the determinant of the functianl dependency the primary key of the new relation
   3. Leabe a copy of the determinant as a foreign key in the original relation
   4. create a referential integrity constraint between the original and new relation
4. Repeat the process until every determinant of every relation is a candidate key