PostgreSQL is an advanced, open-source relational database management system (RDBMS) known for its robustness, scalability, and support for complex queries. It is highly extensible, supporting custom functions, data types, and languages. PostgreSQL is widely used in production environments due to its ACID compliance and strong data integrity features. It also offers excellent concurrency control, making it suitable for high-transaction applications. On Debian 12, PostgreSQL integrates smoothly, providing a reliable platform for database-driven applications.