What Is SQL

SQL, or Structured Query Language, is a database computer language that was designed to manage data in relational database management systems, also known as RDBMS. SQL allows retrieving, deleting and updating information in RDBMS in a relatively simple manner. SQL was originally developed in the 1970’s by IBM. SQL is commonly pronounced as "S-Q-L" by those using the language.

SQL facilitates data sharing and is especially useful when dealing with large sets of relational data. One of the most common uses of SQL language is to retrieve information from a database. For example, if a user were to search a database table called Music for a list of Rolling Stones songs, they would use the following query:

SELECT Songs FROM Music WHERE Artist = ‘Rolling Stones’

SQL is used along with other programming languages to facilitate information retrieval and management. Some of the popular SQL keywords include SELECT, UPDATE, DELETE, INSERT, JOIN, and WHERE. As you can see they are simply words from the English language, which of course have special meaning for the database engine. Things that SQL can do include:

*Execute queries against a database (data retrieval)
*Insert records in a database
*Update records in a database
*Delete records from a database
*Create new databases
*Create new tables in a database
*Create views and stored procedures (depending on specific implementation)

SQL is an ANSI (American National Standards Institute) and ISO (International Organization for Standardization) standard. Although it is a standard of ANSI and ISO, there are multiple vendor-specific versions of the SQL language. They all, however, support the major commands in a similar manner, which complies with the ANSI standard. Open source SQL database solutions include but are not limited to MySQL, Firebird, SQLite, and PostgreSQL.

There have been a number of procedural as well as proprietary SQL extensions that have been created, such as Transact SQL or T-SQL, which is Sybase and Microsoft's proprietary SQL extension. Other common extensions include PL/SQL, which is Oracle's version of SQL, and JET SQL, which is the MS Access SQL version. Just about every modern RDBMS uses SQL as its standard database language. This includes Relational Database Management Systems such as:

*MS SQL Server
*Informix
*Microsoft Access
*Postgres
*MySQL
*Oracle
*Sybase
*DB2

Although all of these use SQL, the SQL dialects will differ, such as Microsoft and Sybase's T-SQL extension. SQL is integral part of modern RDBMS, and allows for easy data management.