SQL (/ˌɛsˌkjuːˈɛl/ (About this soundlisten) S-Q-L, /ˈsiːkwəl/ "sequel"; Structured Query Language) is a domain-specific language used in programming and designed for managing data held in a relational database management system (RDBMS), or for stream processing in a relational data stream management system (RDSMS). It is particularly useful in handling structured data, i.e. data incorporating relations among entities and variables.
SQL offers two main advantages over older read–write APIs such as ISAM or VSAM. Firstly, it introduced the concept of accessing many records with one single command. Secondly, it eliminates the need to specify how to reach a record, e.g. with or without an index.
Originally based upon relational algebra and tuple relational calculus, SQL consists of many types of statements, which may be informally classed as sublanguages, commonly: a data query language (DQL),[a] a data definition language (DDL),[b] a data control language (DCL), and a data manipulation language (DML).[c] The scope of SQL includes data query, data manipulation (insert, update and delete), data definition (schema creation and modification), and data access control. Although SQL is essentially a declarative language (4GL), it also includes procedural elements.
SQL was one of the first commercial languages to use Edgar F. Codd’s relational model. The model was described in his influential 1970 paper, "A Relational Model of Data for Large Shared Data Banks". Despite not entirely adhering to the relational model as described by Codd, it became the most widely used database language.
SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987. Since then, the standard has been revised to include a larger set of features. Despite the existence of standards, most SQL code requires at least some changes before being ported to different database systems.
Nottingham (/ˈnɒtɪŋəm/ (About this soundlisten) NOT-ing-əm) is a city and unitary authority area in Nottinghamshire, England. Part of the East Midlands region, it is 128 miles (206 km) north of London and 45 miles (72 km) northeast of Birmingham. To the west lies Derby, separated by the M1 motorway.
Nottingham has links to the legend of Robin Hood and to the lace-making, bicycle (notably Raleigh bikes) and tobacco industries. It was granted its city charter in 1897, as part of Queen Victoria's Diamond Jubilee celebrations. Nottingham is a tourist destination; in 2018, the city received the second highest amount of overnight visitors in the Midlands and the highest amount in the East Midlands.
In 2017, Nottingham had an estimated population of 329,200. The population of the city proper, compared to its regional counterparts, has been attributed to its historical and tightly-drawn city boundaries. The wider conurbation, which includes many of the city's suburbs, has a population of 768,638. It is the largest urban area in the East Midlands and the second-largest in the Midlands. Its Functional Urban Area, also the largest in the East Midlands, has a population of 919,484. The population of the Nottingham/Derby metropolitan area is estimated to be 1,610,000.
Its metropolitan economy is the seventh largest in the United Kingdom with a GDP of $50.9bn (2014). The city was the first in the East Midlands to be ranked as a sufficiency-level world city by the Globalization and World Cities Research Network.
Nottingham's public transport system won awards prior to 2015, including the largest publicly owned bus network in England, and is also served by Nottingham railway station and the modern Nottingham Express Transit tram system.
It is also a major sporting centre and, in October 2015, was named 'Home of English Sport'. The National Ice Centre, Holme Pierrepont National Watersports Centre and Trent Bridge international cricket ground are all based in or around the city, which is also the home of two professional football teams; the former world's oldest professional league club Notts County and Nottingham Forest, famously two-time winners of the UEFA European Cup under Brian Clough and Peter Taylor in 1979 and 1980. The city also has professional rugby, ice hockey and cricket teams, and the Aegon Nottingham Open, an international tennis tournament on the ATP and WTA tours. This accolade came just over a year after Nottingham was named as the UK's first City of Football.
On 11 December 2015, Nottingham was named a "City of Literature" by UNESCO, joining Dublin, Edinburgh, Melbourne and Prague as one of only a handful in the world. The title reflects Nottingham's literary heritage, with Lord Byron, D. H. Lawrence and Alan Sillitoe having links to the city, as well as a contemporary literary community, a publishing industry and a poetry scene.
The city is served by three universities: the University of Nottingham, Nottingham Trent University and the University of Law; hosting the highest concentration of higher education providers in the East Midlands.