FSQL: A Fuzzy SQL for Fuzzy Databases
Jose Galindo (Universidad de Málaga, Spain), Angelica Urrutia (Universidad Católica del Maule, Chile) and Mario Piattini (Universidad de Castilla-La Mancha, Spain)
Copyright: © 2006
The SQL language was essentially developed by Chamberlin and Boyce (1974) and Chamberlin et al. (1976). In 1986, the American National Standard Institute (ANSI) and the International Standards Organization (ISO) published the standard SQL-86 or SQL1 (ANSI, 1986). In 1989, an extension of the SQL standard, called SQL-89, was published, and SQL2 or SQL-92 was published in 1992 (ANSI, 1992). SQL2 basically provided new types, constraints (such as checks or unique predicates), it supported subqueries in UPDATE and DELETE operations, and in the FROM clause, operator IN, ANY and ALL, CASE constructor, JOIN, UNION, INTERSECT and EXCEPT operators and the modification of base table through views. In the latest version of SQL standard, SQL 2003, major improvements have been made in a number of key areas. Firstly, it has additional object-relational features, which were first introduced in SQL-1999. Secondly, SQL 2003 standard revolutionizes SQL with comprehensive OLAP features and data-mining applications. Thirdly, SQL 2003 integrates popular XML standards into SQL (SQL/XML). Finally, numerous improvements have been made throughout the SQL 2003 standard to refine existing features.