Structured Query Language

As everyone else has been saying, SQL (Structured Query Language) is a computer language that specifically manages databases.  It happens to be one of the first commercial languages developed by IBM in 1970.  In 1986 SQL became a part of the American National Standard Institution (ANSI) and the International Organization for Standards (ISO).  This is to help keep the SQL up to date as with all of the other technology.  There are still some issues, however, with SQL code.  This is due to the standards not being followed as strictly as they should.  This goes along the lines of what John said about interoperability.  The standards are there so that SQL will always remain interoperable.  However, if they aren’t followed as specified, that is when there become problems. 

SQL has 6 major language elements, also brought up by John, which are clauses, expressions, predicates, queries, statements, and insignificant whitespaces.  The use of these elements can be seen in the following figure. 

Note that insignificant whitespaces are “insignificant.”  SQL ignores spaces and therefore they can be used to make the language readable. 

SQL language is used for two major reasons updating data and retrieving data from a database.  Most databases use SQL, however, often times they have their own extensions that will only be used on that specific system.  Although SQL is the only thing needed to do the basic maneuvering of a database, which are: Select, Insert, Update, Delete, Create, and Drop.  For anybody interested in getting a tutorial in SQL they should visit the website SQLCourse.com and it goes through the steps in making a simple database using SQL. 

As David pointed out, SQL is a great resource to have and is much more efficient than using a flat file database.  I like his example about Facebook and filtering all of the information down to what pertains to you.  This put everything into perspective for me.  Reading the Wikipedia page on SQL and other sources I was not following.  Only when I read this example did I understand the function of SQL, which made the other literature easier to comprehend. 

Sources:

http://en.wikipedia.org/wiki/SQL

http://www.sqlcourse.com/index.html