Databases are organized collections of information that facilitate easy access, management, and updating of data. They serve as an abstraction over an operating system’s file system, allowing developers to create, read, update, and delete persistent data efficiently. Databases can be relational, storing data in structured tables with defined relationships, or non-relational (NoSQL), which offer more flexible data storage options. They are essential for web applications, enabling the structured storage of data that can be presented to users in meaningful ways. Popular database management systems include PostgreSQL, MySQL, and SQLite, each catering to different application needs.