Databases

Databases are the structured, persistent storage systems that manage massive volumes of data (e.g., 4.1 zettabytes by 2025) for all modern applications, enabling reliable retrieval via query languages like SQL.

A database is the critical backbone for any data-driven operation: It ensures data integrity, consistency, and high-speed retrieval. This technology encompasses diverse models, from the highly structured Relational Database Management Systems (RDBMS) like PostgreSQL and MySQL to flexible NoSQL types like MongoDB (document) and Redis (in-memory cache). Systems must handle concurrent access, guarantee ACID properties for transactions, and scale efficiently, often utilizing techniques like horizontal sharding to manage petabytes of data. Choosing the right platform (SQL vs. NoSQL) depends entirely on the application's specific requirements (e.g., transactional consistency versus high-volume, flexible data storage).

https://www.postgresql.org