Normalization and Denormalization in PostgreSQL

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. This is achieved through a series of rules that guide the design of tables.

Key Concepts

• Minimizes data duplication.
• Ensures data dependencies are logical.
• Reduces the likelihood of data anomalies.

Normalization Forms

Normalization can be categorized into several forms:

1. First Normal Form (1NF): Ensures that the table has no repeating groups of data.
2. Second Normal Form (2NF): Achieved when the table is in 1NF and all non-key attributes are fully functional dependent on the primary key.
3. Third Normal Form (3NF): Achieved when the table is in 2NF and all attributes are functionally dependent only on the primary key.

Example of Normalization

Consider a table of students:

        CREATE TABLE students (
            id SERIAL PRIMARY KEY,
            name VARCHAR(50),
            course VARCHAR(50)
        );
        

Denormalization is the process of combining tables to improve read performance at the cost of write performance and data integrity.

When to Use Denormalization

• When read performance is critical.
• For reporting and analytics.
• When the database is heavily read-oriented rather than write-oriented.

Example of Denormalization

Combining students and courses into a single table:

        CREATE TABLE student_courses (
            id SERIAL PRIMARY KEY,
            student_name VARCHAR(50),
            course_name VARCHAR(50)
        );
        

Normalization Best Practices

• Always begin with 1NF and progress to higher forms as needed.
• Analyze data relationships carefully.

Denormalization Best Practices

• Use denormalization sparingly and only when necessary.
• Monitor performance impacts regularly.