Editing Database (section)

==Terminology and overview==
Formally, a "database" refers to a set of related data accessed through the use of a "database management system" (DBMS), which is an integrated set of [[Software|computer software]] that allows [[user (computing)|users]] to interact with one or more databases and provides access to all of the data contained in the database (although restrictions may exist that limit access to particular data). The DBMS provides various functions that allow entry, storage and retrieval of large quantities of information and provides ways to manage how that information is organized.

Because of the close relationship between them, the term "database" is often used casually to refer to both a database and the DBMS used to manipulate it.

Outside the world of professional [[information technology]], the term ''database'' is often used to refer to any collection of related data (such as a [[spreadsheet]] or a card index) as size and usage requirements typically necessitate use of a database management system.{{sfn|Ullman|Widom|1997|p=1}}

Existing DBMSs provide various functions that allow management of a database and its data which can be classified into four main functional groups:

* '''Data definition''' – Creation, modification and removal of definitions that detail how the data is to be organized.
* '''Update''' – Insertion, modification, and deletion of the data itself.<ref>{{cite web|url=http://www.merriam-webster.com/dictionary/update|title=Update Definition & Meaning  |work=Merriam-Webster |url-status=live |archive-url=https://web.archive.org/web/20240225065959/https://www.merriam-webster.com/dictionary/update |archive-date= Feb 25, 2024 }}</ref>
* '''Retrieval''' – Selecting data according to specified criteria (e.g., a query, a position in a hierarchy, or a position in relation to other data) and providing that data either directly to the user, or making it available for further processing by the database itself or by other applications. The retrieved data may be made available in a more or less direct form without modification, as it is stored in the database, or in a new form obtained by altering it or combining it with existing data from the database.<ref>{{cite web|url=http://www.merriam-webster.com/dictionary/retrieval|title=Retrieval Definition & Meaning  |work=Merriam-Webster |url-status=live |archive-url= https://web.archive.org/web/20230627174611/https://www.merriam-webster.com/dictionary/retrieval |archive-date= Jun 27, 2023 }}</ref>
* '''Administration''' – Registering and monitoring users, enforcing data security, monitoring performance, maintaining data integrity, dealing with concurrency control, and recovering information that has been corrupted by some event such as an unexpected system failure.<ref>{{cite web|url=http://www.merriam-webster.com/dictionary/administration|title=Administration Definition & Meaning |work=Merriam-Webster |url-status=live |archive-url=https://web.archive.org/web/20231206055116/https://www.merriam-webster.com/dictionary/administration |archive-date= Dec 6, 2023 }}</ref>

Both a database and its DBMS conform to the principles of a particular [[database model]].{{sfn|Tsitchizris| Lochovsky| 1982}} "Database system" refers collectively to the database model, database management system, and database.{{sfn|Beynon-Davies|2003}}

Physically, database [[Server (computing)|servers]] are dedicated computers that hold the actual databases and run only the DBMS and related software. Database servers are usually [[multiprocessor]] computers, with generous memory and [[redundant array of independent disks|RAID]] disk arrays used for stable storage. Hardware database accelerators, connected to one or more servers via a high-speed channel, are also used in large-volume [[Transaction processing system|transaction processing environments]]. DBMSs are found at the heart of most [[database application]]s. DBMSs may be built around a custom [[computer multitasking|multitasking]] [[Kernel (operating system)|kernel]] with built-in [[Computer network|networking]] support, but modern DBMSs typically rely on a standard [[operating system]] to provide these functions.{{citation needed|reason=This has become a mish-mash people's opinion and while boardly accurate may be in places undue and ignored e.g. SAN storage and needs cited rewrite from scrach|date=January 2020}}

Since DBMSs comprise a significant [[Market (economics)|market]], computer and storage vendors often take into account DBMS requirements in their own development plans.{{sfn|Nelson|Nelson|2001}}

Databases and DBMSs can be categorized according to the database model(s) that they support (such as [[Relational database|relational]] or [[XML]]), the type(s) of computer they run on (from a [[Computer cluster|server cluster]] to a [[mobile phone]]), the [[query language]](s) used to access the database (such as SQL or [[XQuery]]), and their internal engineering, which affects performance, [[scalability]], resilience, and security.