Database

An SQL select statement and its result.

A database is an organized collection of data, generally stored and accessed electronically from a computer system. Where databases are more complex they are often developed using formal design and modeling techniques.

The database management system (DBMS) is the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS software additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a "database system". Often the term "database" is also used to loosely refer to any of the DBMS, the database system or an application associated with the database.

Computer scientists may classify database-management systems according to the database models that they support. Relational databases became dominant in the 1980s. These model data as rows and columns in a series of tables, and the vast majority use SQL for writing and querying data. In the 2000s, non-relational databases became popular, referred to as NoSQL because they use different query languages.

Terminology and overview

Formally, a "database" refers to a set of related data and the way it is organized. Access to this data is usually provided by a "database management system" (DBMS) consisting of an integrated set of computer software that allows 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.[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 define the organization of the data.
  • Update – Insertion, modification, and deletion of the actual data.[2]
  • Retrieval – Providing information in a form directly usable or for further processing by other applications. The retrieved data may be made available in a form basically the same as it is stored in the database or in a new form obtained by altering or combining existing data from the database.[3]
  • 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.[4]

Both a database and its DBMS conform to the principles of a particular database model.[5] "Database system" refers collectively to the database model, database management system, and database.[6]

Physically, database 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 RAID disk arrays used for stable storage. RAID is used for recovery of data if any of the disks fail. Hardware database accelerators, connected to one or more servers via a high-speed channel, are also used in large volume transaction processing environments. DBMSs are found at the heart of most database applications. DBMSs may be built around a custom multitasking kernel with built-in networking support, but modern DBMSs typically rely on a standard operating system to provide these functions.

Since DBMSs comprise a significant market, computer and storage vendors often take into account DBMS requirements in their own development plans.[7]

Databases and DBMSs can be categorized according to the database model(s) that they support (such as relational or XML), the type(s) of computer they run on (from a 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.

Other Languages
Afrikaans: Databasis
አማርኛ: ዳታቤዝ
العربية: قاعدة بيانات
aragonés: Base de datos
asturianu: Base de datos
azərbaycanca: Məlumat bazası
বাংলা: ডেটাবেজ
беларуская: База даных
беларуская (тарашкевіца)‎: База зьвестак
български: База данни
Boarisch: Datnbank
bosanski: Baza podataka
brezhoneg: Stlennvon
català: Base de dades
čeština: Databáze
Cymraeg: Cronfa ddata
dansk: Database
Deutsch: Datenbank
eesti: Andmebaas
Ελληνικά: Βάση δεδομένων
español: Base de datos
Esperanto: Datumbazo
euskara: Datu-base
français: Base de données
Frysk: Database
हिन्दी: डेटाबेस
hrvatski: Baza podataka
Bahasa Indonesia: Pangkalan data
interlingua: Base de datos
íslenska: Gagnagrunnur
italiano: Base di dati
Basa Jawa: Basis data
қазақша: Дерекқор
kurdî: Danegeh
latviešu: Datubāze
lietuvių: Duomenų bazė
Lingua Franca Nova: Banco de datos
lumbaart: Database
magyar: Adatbázis
македонски: База на податоци
മലയാളം: ഡാറ്റാബേസ്
Bahasa Melayu: Pangkalan data
Mirandés: Base de dados
မြန်မာဘာသာ: ဒေတာဘေ့စ်
Nederlands: Database
norsk: Database
norsk nynorsk: Database
олык марий: Ыҥпалыпого
oʻzbekcha/ўзбекча: Maʼlumotlar bazasi
ਪੰਜਾਬੀ: ਡਾਟਾਬੇਸ
پښتو: توكبنسټ
polski: Baza danych
português: Banco de dados
română: Bază de date
русский: База данных
Scots: Database
Seeltersk: Doatenboank
sicilianu: Databbasi
Simple English: Database
slovenčina: Databáza
slovenščina: Podatkovna zbirka
کوردی: بنکەدراوە
српски / srpski: База података
srpskohrvatski / српскохрватски: Baza podataka
suomi: Tietokanta
svenska: Databas
Tagalog: Database
татарча/tatarça: Бирелмәләр нигезе
తెలుగు: డేటాబేస్
Türkçe: Veri tabanı
українська: База даних
اردو: ڈیٹا بیس
Tiếng Việt: Cơ sở dữ liệu
Winaray: Database
吴语: 数据库
粵語: 資料庫
中文: 数据库