A **database** is an organized collection of [[Data|data]] stored and accessed electronically. Small databases can be stored on a [[File system|file system]], while large databases are hosted on [[Computer cluster|computer clusters]] or [[Cloud computing|cloud infrastructure]]. The design of databases spans formal techniques and practical considerations, including [[Data modeling|data modeling]], efficient data representation and storage, [[Query language|query languages]], [[Data security|security]] and [[Data privacy|privacy]] of sensitive data, and [[Distributed computing|distributed computing]] issues, including supporting [[Concurrent computing|concurrent access]] and [[Fault tolerance|fault tolerance]]. A [[Database management system]] (DBMS) is the [[Software|software]] that interacts with end users, applications, and the database itself to capture and analyze data. The DBMS additionally encompasses the core facilities provided to administer the database. The combined system of the database, the DBMS, and the associated applications is referred to as a **database system**. The most prevalent type of DBMS is the [[Relational database|relational database management system]] (RDBMS), which uses a [[Relational model|relational model]] based on [[Set theory|set theory]] and [[Predicate logic|predicate logic]], organizing data into [[Table (database)|tables]] consisting of rows and columns. [[SQL|SQL]] is the standard [[Query language|query language]] for relational databases and is used by most RDBMS products. Other database models include the [[Key–value database|key–value store]], [[Document-oriented database|document store]], [[Graph database|graph database]], and [[Column-oriented DBMS|column-family store]], which are often grouped under the umbrella term [[NoSQL|NoSQL]]. Databases and database management systems have evolved significantly since their inception in the 1960s. Early systems such as [[IBM]]'s [[Information Management System|IMS]] used [[Hierarchical database model|hierarchical]] and [[Network model|network models]]. The relational model, proposed by [[Edgar F. Codd|Edgar F. Codd]] in 1970, became dominant during the 1980s and remains widely used. The growth of the [[World Wide Web|web]] and the need to handle large volumes of [[Unstructured data|unstructured data]] at scale led to the rise of NoSQL databases in the late 2000s. More recently, [[NewSQL]] systems have sought to combine the scalability of NoSQL with the [[ACID|transactional guarantees]] of relational databases, while [[Cloud database|cloud-hosted database services]] offered by providers such as [[Amazon Web Services]], [[Google Cloud Platform]], and [[Microsoft Azure]] have become a standard deployment model for organizations of all sizes.