DBMS

Normalization

Hard
EST. TIME: 40 min

Normalization

To analyze and decompose schemas for Normalization (1NF to 5NF) to reduce redundancy.

Theory & Concepts

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1. Introduction

Normalization is a systematic approach of decomposing tables to eliminate data redundancy (repetition) and undesirable characteristics like Insertion, Update, and Deletion Anomalies.

2. Normal Forms

First Normal Form (1NF)

Rule: Each column must contain atomic values (single value, not a list).
Fix: Create a separate row for each value or separate table.

Second Normal Form (2NF)

Rule: Must be in 1NF + No Partial Dependency (All non-key attributes must depend on the *entire* primary key).
Fix: Move partial dependent data to a new table.

Third Normal Form (3NF)

Rule: Must be in 2NF + No Transitive Dependency (Non-key attributes should not depend on other non-key attributes).
Fix: Move transitive data to a new table.

BCNF (Boyce-Codd Normal Form)

Rule: A stricter version of 3NF. For every functional dependency X → Y, X must be a super key.

3. Summary

Calculated normalization is a trade-off. While higher normal forms reduce redundancy, they often require more Joins which can slow down read performance. 3NF is usually considered sufficient for most business applications.

Procedure

1

Identify Violations

Look at the raw un-normalized table and identify multi-valued attributes (Violation of 1NF) or partial dependencies.

2

Decompose

Use the split tool to break the table into two, selecting the appropriate Primary and Foreign keys.

3

Verify

Check if the resulting tables satisfy the next Normal Form conditions.

Learning Resources

Animated Lecture

Normalization in DBMS

Reference Notes

Normalization Quick Guide

Self Quiz

Normalization Quiz

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Launch the virtual simulator to perform database operations and see SQL queries in action.

Lab Status

Active Simulation

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