SQL Query Language SQL query language is nonprocedural.A query takes as input several tables (possibly only one)and always returns a single table. Example to find all instructors in Comp.Sci.dept select name from instructor where dept_name ='Comp.Sci.' SQL is NOT a Turing machine equivalent language To be able to compute complex functions SQL is usually embedded in some higher-level language Application programs generally access databases through one of Language extensions to allow embedded SQL Application program interface (e.g.,ODBC/JDBC)which allow SQL queries to be sent to a database Database System Concepts-7th Edition 1.19 ©Silberscha乜，Korth and SudarshanDatabase System Concepts - 7 1.19 ©Silberschatz, Korth and Sudarshan th Edition SQL Query Language ▪ SQL query language is nonprocedural. A query takes as input several tables (possibly only one) and always returns a single table. ▪ Example to find all instructors in Comp. Sci. dept select name from instructor where dept_name = 'Comp. Sci.' ▪ SQL is NOT a Turing machine equivalent language ▪ To be able to compute complex functions SQL is usually embedded in some higher-level language ▪ Application programs generally access databases through one of • Language extensions to allow embedded SQL • Application program interface (e.g., ODBC/JDBC) which allow SQL queries to be sent to a database