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.
Corby is a town and borough in the county of Northamptonshire, England.
It is located 23 miles (37 km) north-east of the county town, Northampton. At the 2011 Census the town had a population of 54,927 and the borough had a population of 61,255. Figures released in March 2010 revealed that Corby has the fastest growing population in both Northamptonshire and the whole of England. The borough of Corby borders onto the borough of Kettering, the district of East Northamptonshire, the district of Harborough and the unitary authority county of Rutland. The town was at one time known locally as "Little Scotland" due to the large number of Scottish workers who came to Corby for its steelworks. Recently, Corby has undergone a large regeneration process with the opening of Corby railway station and Corby International Pool in 2009 and the Corby Cube building opening in 2010. This is home to Corby Borough Council offices and also houses a 450-seat theatre, a public library and other community amenities.