Learn PostgreSQL

1. Introduction

PostgreSQL is an advanced open-source relational database management system (RDBMS). It uses SQL and extends it with powerful enterprise features.

Often called Postgres, it is known for reliability, extensibility, and standards compliance.

2. Key Features

• ACID compliant transactions
• Advanced indexing
• JSON & JSONB support
• Full-text search
• Extensions support
• Concurrency control (MVCC)

3. Architecture Overview

Components:

• Server process
• Client applications
• Database cluster
• Tablespaces

Postgres uses a client-server model.

4. Installation & Tools

Common tools:

• psql (CLI)
• pgAdmin (GUI)
• DBeaver

5. Database Operations

CREATE DATABASE company;

\c company

DROP DATABASE company;

6. Data Types

Postgres supports advanced types:

• Numeric
• Text
• Boolean
• Date/Time
• UUID
• Array
• JSON/JSONB
• HSTORE

7. JSONB Example

CREATE TABLE products (
  id SERIAL PRMARY KEY,
  data JSONB
);
 
INSERT INTO products (data)
VALUES ('{"name":"Laptop","price":1200}');

8. Indexing

Types:

• B-Tree (default)
• Hash
• GIN
• GiST
• BRIN

Example:

CREATE INDEX idx_json
ON products USING GIN (data);

9. Constraints

• PRIMARY KEY
• FOREIGN KEY
• UNIQUE
• CHECK
• EXCLUSION

10. Transactions

BEGIN;
UPDATE accounts SET balance = balance - 100 WHERE id=1;
UPDATE accounts SET balance = balance + 100 WHERE id=2;
COMMIT;

11. MVCC (Multi-Version Concurrency Control)

Allows multiple users to access data without locking conflicts.

12. Views & Materialized Views

Materialized views store query results physically for performance.

13. Functions & Stored Procedures

Written in:

• PL/pgSQL
• Python
• Perl
• C

14. Extensions

Popular extensions:

• PostGIS (geospatial)
• pg_trgm (text similarity)
• uuid-ossp

15. Replication & Scaling

• Streaming replication
• Logical replication
• Read replicas

16. Security

• Role-based access
• SSL connections
• Row-level security

17. Use Cases

• Web applications
• GIS systems
• Financial platforms
• Analytics

18. Advantages

• Extremely feature rich
• Open source
• Highly extensible

19. Limitations

• Heavier than MySQL
• More complex tuning