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.
Lincolnshire (abbreviated Lincs.) is a county in the East Midlands of England, with a long coastline on the North Sea to the east. It borders Norfolk to the south-east, Cambridgeshire to the south, Rutland to the south-west, Leicestershire and Nottinghamshire to the west, South Yorkshire to the north-west, and the East Riding of Yorkshire to the north. It also borders Northamptonshire in the south for just 20 yards (19 m), England's shortest county boundary. The county town is the city of Lincoln, where the county council has its headquarters.
The ceremonial county of Lincolnshire consists of the non-metropolitan county of Lincolnshire and the area covered by the unitary authorities of North Lincolnshire and North East Lincolnshire. Part of the ceremonial county is in the Yorkshire and the Humber region of England, and most is in the East Midlands region. The county is the second-largest of the English ceremonial counties and one that is predominantly agricultural in land use. The county is fourth-largest of the two-tier counties, as the unitary authorities of North Lincolnshire and North East Lincolnshire are not included.
The county has several geographical sub-regions, including the rolling chalk hills of the Lincolnshire Wolds. In the south-east are the Lincolnshire Fens (south-east Lincolnshire), the Carrs (similar to the Fens but in north Lincolnshire), the industrial Humber Estuary and North Sea coast around Grimsby and Scunthorpe, and in the south-west of the county, the Kesteven Uplands, rolling limestone hills in the district of South Kesteven.