Data Normalization
Purpose
Section titled “Purpose”Normalization eliminates data redundancy and ensures data integrity by organizing data into properly structured tables.
Normal Forms
Section titled “Normal Forms”First Normal Form (1NF)
Section titled “First Normal Form (1NF)”- Each column contains atomic (indivisible) values
- No repeating groups or arrays
- Each row must be unique
Second Normal Form (2NF)
Section titled “Second Normal Form (2NF)”- Must be in 1NF
- No partial dependencies on composite primary keys
- All non-key attributes fully depend on entire primary key
Third Normal Form (3NF)
Section titled “Third Normal Form (3NF)”- Must be in 2NF
- No transitive dependencies
- Non-key attributes don’t depend on other non-key attributes
Boyce-Codd Normal Form (BCNF)
Section titled “Boyce-Codd Normal Form (BCNF)”- Stronger version of 3NF
- Every determinant must be a candidate key
Benefits
Section titled “Benefits”- Reduces data redundancy
- Improves data consistency
- Easier maintenance
- Better storage efficiency
Denormalization
Section titled “Denormalization”Sometimes tables are intentionally denormalized for:
- Performance optimization
- Simplified queries
- Reporting requirements
Balance between normalization benefits and performance needs.