A database is a structured collection of data. The data is typically organised to model relevant aspects of reality (for example, the availability of rooms in hotels), in a way that supports processes requiring this information (for example, finding a hotel with vacancies). Once the room is booked the availability of the room on the dates set are no longer available

The term database is correctly applied to the data and their supporting data structures, and not to the database management system. The database data collection with database management system is called a database system.

The term database system implies that the data is managed to some level of quality and this in turn often implies the use of a general-purpose database management system. A general-purpose database management system is typically a complex software system that meets many usage requirements to properly maintain its databases which are often large and complex.

This is specially the case with client-server, near-real time transactional systems, in which multiple users have access to data, data is concurrently entered and inquired for in ways that preclude single-thread batch processing. Most of the complexity of those requirements are still present with personal, desktop-based database systems.

Well known DBMSs include Oracle, Sybase, FoxPro,IBM DB2, Linter, Microsoft Access, Microsoft SQL Server, MySQL (default on an Apache server), PostgreSQL and SQLite.

A database is not generally portable across different database management system, but different database management systems can inter-operate to some degree by using standards like Structured query lists and Open Database Connectivity together to support a single application built over more than one database. A database management system also needs to provide effective run-time execution to properly support (e.g., in terms of performance, availability, and security) as many database end-users as needed.

Having a database attached to a web site requires additional measures to be put in place such as Terms & Conditions, Privacy, and Security to cover the Data protection Act. If collecting personal data within the United Kingdom you must also supply a postal address