Structured Query Language (SQL) is a specialized language for updating, deleting, and requesting information from databases. SQL is an ANSI and ISO standard, and is the de facto database query language. A variety of established database products support SQL, including products from Oracle and Microsoft SQL Server. It is widely used in both industry and academia, often for enormous, complex datbases. (Base, 2013).SQL was developed in the 1970’s by IBM to initially manipulate and retrieve data in IBM system R. The SQL language was standardized in 1986 by the American National Standards Institute (ANSI); however, later releases were released as International Organization Standardization (ISO) standards. (Inc., 2013)
Although IBM authored SQL, the first SQL implementation was provided by Oracle Corporation (then called Relational Software Inc.). Early commercial implementations were concentrated on midsized UNIX-based DBMSs, such as Oracle, Ingres, and Informix. IBM followed in 1981 with SQL/DS, the forerunner to DB2, which debuted in 1983. (Unknown, 2010)
ANSI published the first SQL standard (SQL-86) in 1986. An international version of the standard issued by ISO appeared in 1987. A significant update to SQL-86 was released in 1989 (SQL-89). Virtually, all relational DBMSs that you encounter today support most of the 1986 standard. (Unknown, 2010)
In 1992, the standard was revised again (SQL-92), adding more capabilities to the language. Because SQL-92 was s superset of SQL-89, older database application programs ran under the new standard with minimal modifications. In fact, until October 1996, DBMS vendors could submit their products to NIST (National Institute for Standards and Technology) for verification of SQL standard compliance. The testing and certification process provided significant motivation for DBMS vendors to adhere to the SQL standard. Although discounting standard compliance testing saves vendors money, it also makes it easier for products to diverge from the standard. (Unknown, 2010)
In SQL-92 standard was superseded by SQL:1999, which was once again a superset of the preceding standard. The primary new features of SQL:1999 supported the object-relational data model. (Unknown, 2010)
The SQL:1999 standard also adds extension to SQL to allow methods / functions/ procedures to be written in SQL or to be written in another programming language such as C++ or Java and then invoked from within another SQL statement. As a result, SQL becomes less “relational,” a trend decried by some relational purists. (Unknown, 2010)
Even the full SQL:1999 standard does not turn SQL into a complete, stand-alone programming language. In particular, SQL lacks I/O statements. This makes perfect sense, since SQL should be implementation and operating system independent. However, the full SQL:1999 standard does includes operations such as selection and iteration that makes it computationally complete. These language features, which are more typical of general-purpose programming language, are used when writing stored procedures and triggers. (Unknown, 2010)
The SQL standard has been updated three times since the appearance of SQL:1999 in versions named SQL:2003, SQL:2006, and SQL:2008. As well as fleshing out the capabilities for the core relational features and extending object-relational support, these revisions have added support for XML (Extended Markup Language). XML is a platform-independent method for