PostgreSQL

PostgreSQL is a powerful, open source object-relational database system with over 35 years of active development.

Features

• Highly extensible (supports custom types and functions)
• Deep SQL compliance
• Excellent concurrency and performance

Code Example

Creating a table and using modern JSONB features:

CREATE TABLE users (
    id SERIAL PRIMARY KEY,
    username VARCHAR(50) UNIQUE NOT NULL,
    preferences JSONB DEFAULT '{}'::jsonb
);

INSERT INTO users (username, preferences) 
VALUES ('admin', '{"theme": "dark"}');