normalization

1. Normalization in DBMS
NEB Class 12 - Computer Science

2. Introduction to Normalization
• Normalization is a process to organize data in a database.
• Reduces redundancy (duplicate data) and improves data integrity.
• Divides larger tables into smaller, related tables.
• Ensures data is stored efficiently.

3. Need for Normalization
• Avoids data duplication.
• Prevents update, insert, and delete anomalies.
• Makes database more flexible and efficient.
• Improves consistency and accuracy of data.

4. Anomalies in Databases
• Update Anomaly: Changing data in one place but not another.
• Insert Anomaly: Cannot insert data without another piece of data.
• Delete Anomaly: Deleting data unintentionally removes other important data.

5. First Normal Form (1NF)
• Ensures each column has atomic (indivisible) values.
• Each record is unique (no duplicate rows).
• Example: Splitting full name into first and last name.

6. Second Normal Form (2NF)
• Must already be in 1NF.
• All non-key attributes depend on the whole primary key.
• Removes partial dependency.

7. Third Normal Form (3NF)
• Must already be in 2NF.
• No transitive dependency (non-key attribute depending on another non-key attribute).
• Improves data independence.

8. Boyce-Codd Normal Form (BCNF)
• A stronger version of 3NF.
• Handles anomalies not covered by 3NF.
• Every determinant must be a candidate key.

9. Advantages of Normalization
• Eliminates redundant data.
• Ensures logical data storage.
• Improves query performance.
• Makes maintenance easier.

10. Summary
• Normalization organizes database tables to reduce redundancy.
• Follows step-by-step process: 1NF → 2NF → 3NF → BCNF.
• Prevents anomalies and maintains data integrity.