About Me
Databases
1 Introduction to Databases
1-1 Definition of Databases
1-2 Importance of Databases in Modern Applications
1-3 Types of Databases
1-3 1 Relational Databases
1-3 2 NoSQL Databases
1-3 3 Object-Oriented Databases
1-3 4 Graph Databases
1-4 Database Management Systems (DBMS)
1-4 1 Functions of a DBMS
1-4 2 Popular DBMS Software
1-5 Database Architecture
1-5 1 Centralized vs Distributed Databases
1-5 2 Client-Server Architecture
1-5 3 Cloud-Based Databases
2 Relational Database Concepts
2-1 Introduction to Relational Databases
2-2 Tables, Rows, and Columns
2-3 Keys in Relational Databases
2-3 1 Primary Key
2-3 2 Foreign Key
2-3 3 Composite Key
2-4 Relationships between Tables
2-4 1 One-to-One
2-4 2 One-to-Many
2-4 3 Many-to-Many
2-5 Normalization
2-5 1 First Normal Form (1NF)
2-5 2 Second Normal Form (2NF)
2-5 3 Third Normal Form (3NF)
2-5 4 Boyce-Codd Normal Form (BCNF)
3 SQL (Structured Query Language)
3-1 Introduction to SQL
3-2 SQL Data Types
3-3 SQL Commands
3-3 1 Data Definition Language (DDL)
3-3 1-1 CREATE
3-3 1-2 ALTER
3-3 1-3 DROP
3-3 2 Data Manipulation Language (DML)
3-3 2-1 SELECT
3-3 2-2 INSERT
3-3 2-3 UPDATE
3-3 2-4 DELETE
3-3 3 Data Control Language (DCL)
3-3 3-1 GRANT
3-3 3-2 REVOKE
3-3 4 Transaction Control Language (TCL)
3-3 4-1 COMMIT
3-3 4-2 ROLLBACK
3-3 4-3 SAVEPOINT
3-4 SQL Joins
3-4 1 INNER JOIN
3-4 2 LEFT JOIN
3-4 3 RIGHT JOIN
3-4 4 FULL JOIN
3-4 5 CROSS JOIN
3-5 Subqueries and Nested Queries
3-6 SQL Functions
3-6 1 Aggregate Functions
3-6 2 Scalar Functions
4 Database Design
4-1 Entity-Relationship (ER) Modeling
4-2 ER Diagrams
4-3 Converting ER Diagrams to Relational Schemas
4-4 Database Design Best Practices
4-5 Case Studies in Database Design
5 NoSQL Databases
5-1 Introduction to NoSQL Databases
5-2 Types of NoSQL Databases
5-2 1 Document Stores
5-2 2 Key-Value Stores
5-2 3 Column Family Stores
5-2 4 Graph Databases
5-3 NoSQL Data Models
5-4 Advantages and Disadvantages of NoSQL Databases
5-5 Popular NoSQL Databases
6 Database Administration
6-1 Roles and Responsibilities of a Database Administrator (DBA)
6-2 Database Security
6-2 1 Authentication and Authorization
6-2 2 Data Encryption
6-2 3 Backup and Recovery
6-3 Performance Tuning
6-3 1 Indexing
6-3 2 Query Optimization
6-3 3 Database Partitioning
6-4 Database Maintenance
6-4 1 Regular Backups
6-4 2 Monitoring and Alerts
6-4 3 Patching and Upgrading
7 Advanced Database Concepts
7-1 Transactions and Concurrency Control
7-1 1 ACID Properties
7-1 2 Locking Mechanisms
7-1 3 Isolation Levels
7-2 Distributed Databases
7-2 1 CAP Theorem
7-2 2 Sharding
7-2 3 Replication
7-3 Data Warehousing
7-3 1 ETL Processes
7-3 2 OLAP vs OLTP
7-3 3 Data Marts and Data Lakes
7-4 Big Data and Databases
7-4 1 Hadoop and HDFS
7-4 2 MapReduce
7-4 3 Spark
8 Emerging Trends in Databases
8-1 NewSQL Databases
8-2 Time-Series Databases
8-3 Multi-Model Databases
8-4 Blockchain and Databases
8-5 AI and Machine Learning in Databases
9 Practical Applications and Case Studies
9-1 Real-World Database Applications
9-2 Case Studies in Different Industries
9-3 Hands-On Projects
9-4 Troubleshooting Common Database Issues
10 Certification Exam Preparation
10-1 Exam Format and Structure
10-2 Sample Questions and Practice Tests
10-3 Study Tips and Resources
10-4 Final Review and Mock Exams
2-5-3 Third Normal Form (3NF) Explained

2-5-3 Third Normal Form (3NF) Explained

Key Concepts

Third Normal Form (3NF)

Third Normal Form (3NF) is a database normalization technique that builds upon the principles of First Normal Form (1NF) and Second Normal Form (2NF). 3NF ensures that a database schema is free of transitive dependencies, meaning that non-key attributes are dependent only on the primary key and not on other non-key attributes.

Transitive Dependency

Transitive Dependency occurs when a non-key attribute is functionally dependent on another non-key attribute rather than directly on the primary key. This can lead to data redundancy and anomalies. 3NF aims to eliminate these transitive dependencies by ensuring that all non-key attributes are directly dependent on the primary key.

Normalization

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. Achieving 3NF is a critical step in this process, as it ensures that the database is well-structured and free of unnecessary dependencies.

Examples and Analogies

Example: Employee Database

Consider an "Employees" table with columns: "EmployeeID," "DepartmentID," and "DepartmentName." In this table, "DepartmentName" is functionally dependent on "DepartmentID," which is not the primary key. To achieve 3NF, we should split this table into two separate tables: "Employees" (with "EmployeeID" and "DepartmentID") and "Departments" (with "DepartmentID" and "DepartmentName"). This eliminates the transitive dependency and ensures that each non-key attribute is directly dependent on the primary key.

Analogy: Library System

Think of a library system with a "Books" table containing "BookID," "AuthorID," and "AuthorAddress." Here, "AuthorAddress" is dependent on "AuthorID," which is not the primary key. To achieve 3NF, we should create separate tables for "Books" (with "BookID" and "AuthorID") and "Authors" (with "AuthorID" and "AuthorAddress"). This ensures that each piece of information is stored in the most appropriate table, reducing redundancy and improving data integrity.

Conclusion

Understanding Third Normal Form (3NF) is essential for designing efficient and well-structured databases. By eliminating transitive dependencies and ensuring that non-key attributes are directly dependent on the primary key, 3NF helps maintain data integrity and reduce redundancy. Visualizing these concepts through practical examples and analogies can enhance your understanding and application of 3NF in database management.

© 2024 Ahmed Baheeg Khorshid. All rights reserved.