In database programming, structured query language (SQL) is a domain-specific language that programmers and database administrators use to store and manipulate data, particularly structured data controlled by relational database systems. Relational data is when pieces of data have a relation to variables in the database. SQL gained in popularity over similar earlier languages because it allowed users to call up many pieces of data with a single command and did away with the need for an index of the information in the database. A variety of careers use structured query language (SQL), including technical jobs as a database administrator, server management specialist, web designer, hosting technician, software developer, and software quality assurance, as well as positions in business analysis and business intelligence.