SQL overview

SQL (Structured Query Language) is one of the main reasons for the commercial success of relational databases. The ANSI (American National Standards Institute) and the ISO (International Standards Organization) developed in 1986 the first SQL-version with the name SQL-86 or SQL1. In 1992 a second and more extended standard with the name of SQL-92 or SQL2 was established. The latest standard includes XML, dates from 1999 and is therefore called SQL-99 or SQL3. With the use of SQL in most commercial database systems the migration from one system to another has become easier for the user. In the ideal case, the user need not consider which system is used because query formation in SQL remains the same.