What is Database Normalization?

Database normalization is a process used to organize a database into tables and columns in such a way that each table represents a single entity or relationship, and each column contains only atomic (indivisible) values. The main purpose of normalization is to minimize data redundancy and improve data integrity by ensuring that each piece of data is stored in only one place.

There are several levels of normalization, known as normal forms, which are typically referred to as NF1 through NF6 (with NF1 being the most basic and NF6 being the most restrictive). The most commonly used normal forms are:

1. First Normal Form (NF1): Ensures that each column contains only atomic values and there are no repeating groups or arrays.

   • Example: If you have a table with columns for "Student ID," "Name," and "Courses Taken" where "Courses Taken" is a list like "Math, Science," it violates NF1. It should be split into a separate table for courses taken, with each course on a separate row.

2. Second Normal Form (NF2): Builds on NF1 and requires that every non-key column be fully functional dependent on the primary key.

   • Example: If you have a table with "Order ID," "Product ID," "Product Name," and "Product Price," and "Product Name" and "Product Price" depend only on "Product ID" and not on "Order ID," it violates NF2. It should be split into separate tables for orders and products.

3. Third Normal Form (NF3): Further refines NF2 by requiring that there be no transitive functional dependencies; non-key columns should depend only on the primary key.

   • Example: If you have a table with "Student ID," "Student Name," "Course ID," and "Course Instructor," where "Course Instructor" depends on "Course ID" and not directly on "Student ID," it violates NF3. It should be split into separate tables for students, courses, and instructors.

Normalization helps in reducing anomalies like insertion, update, and deletion anomalies, which can occur when data is duplicated across multiple places in a database.

In the context of cloud computing, services like Tencent Cloud's Cloud Database MySQL provide robust support for database normalization through features like automatic schema optimization, data consistency checks, and efficient storage management. These services help in managing large datasets more effectively and ensuring high availability and reliability of the database operations.