**Course Title:** SQLite Mastery: Lightweight Database Management **Section Title:** SQLite Database Design and Normalization **Topic:** Understanding normalization and normal forms (1NF, 2NF, 3NF) ### Introduction to Normalization Normalization is a fundamental concept in database design that helps eliminate data redundancy and inconsistency. In this topic, we will explore the basics of normalization and discuss three normal forms (1NF, 2NF, 3NF) to help you design a robust and scalable SQLite database. ### What is Normalization? Normalization is the process of organizing data in a database to minimize data redundancy and dependency. It involves dividing large tables into smaller, more manageable tables, and defining relationships between them. Normalization helps to: * Eliminate data duplication and inconsistency * Improve data integrity and scalability * Simplify database maintenance and updates ### First Normal Form (1NF) A table is in 1NF if it meets the following conditions: * Each row contains a unique combination of values. * Each column contains only atomic values (single values, not lists or sets). * No repeating groups or arrays. Example of a table in 1NF: | Customer ID (Primary Key) | Name | Address | | --- | --- | --- | | 1 | John Smith | 123 Main St | | 2 | Jane Doe | 456 Elm St | In this example, each row has a unique customer ID, and each column contains only atomic values. ### Second Normal Form (2NF) A table is in 2NF if it meets the following conditions: * It is in 1NF. * Each non-key attribute (column) depends on the entire primary key. Example of a table in 2NF: | Order ID (Primary Key) | Customer ID (Foreign Key) | Order Date | | --- | --- | --- | | 1 | 1 | 2022-01-01 | | 2 | 1 | 2022-01-15 | | 3 | 2 | 2022-02-01 | In this example, the order date depends on the entire primary key (order ID), and the customer ID is a foreign key that references the customers table. ### Third Normal Form (3NF) A table is in 3NF if it meets the following conditions: * It is in 2NF. * If a table is in 2NF, and a non-key attribute depends on another non-key attribute, then it should be moved to a separate table. Example of a table in 3NF: **Customers Table** | Customer ID (Primary Key) | Name | Address | | --- | --- | --- | | 1 | John Smith | 123 Main St | | 2 | Jane Doe | 456 Elm St | **Orders Table** | Order ID (Primary Key) | Customer ID (Foreign Key) | Order Date | | --- | --- | --- | | 1 | 1 | 2022-01-01 | | 2 | 1 | 2022-01-15 | | 3 | 2 | 2022-02-01 | **Order Items Table** | Order ID (Foreign Key) | Product ID (Foreign Key) | Quantity | | --- | --- | --- | | 1 | 1 | 2 | | 1 | 2 | 1 | | 2 | 3 | 3 | In this example, the order items table depends on the orders table, which depends on the customers table. This design eliminates data redundancy and improves data integrity. ### Conclusion Normalization is a crucial aspect of database design that helps eliminate data redundancy and inconsistency. By understanding the three normal forms (1NF, 2NF, 3NF), you can design a robust and scalable SQLite database that meets the needs of your application. Remember to normalize your database to ensure data integrity and scalability. **For Further Reading:** * [SQLite Documentation: Normalization](https://www.sqlite.org/ normalization.html) * [Wikipedia: Database Normalization](https://en.wikipedia.org/wiki/ Database_normalization) **Ask for Help:** If you have any questions or need further clarification on normalization and normal forms, please leave a comment below. **Next Topic:** In the next topic, we will discuss handling denormalization in SQLite for performance optimization.