SQL - overview

Just like Elda and john said, SQL is a programming language used to sort through relational databases. It is commonly regarded as “the standard computer database language”[1]. It is used in personal computers, cell phones, entertainment systems, and many other devices. What is very useful about it is that it is very standardized and thus able to communicate with just about any computer database. SQL is used to organize and retrieve information stored in computer databases. SQL logic is pretty intuitive, and is represented by the figure below:

When information from the database needs to be retrieved, SQL makes a request to the database management system (DBMS), which returns the requested information.  SQL is not the DBMS itself, though; it is simply a language used to communicate with it. In practice, SQL is much more involved than that. Its functions include data definition, data retrieval, data manipulation, access control, data sharing, and data integrity.

I would like to elaborate on John Scanlon’s comparison of SQL to other computer language: SQL can be used for databases only. It has only about 40 statements to control and manage the database and it is not a complete language like C++ or Java. This is why it can be embedded in other language but the opposite scenario is impossible.

Because it is short, it is very easy to learn and use and has a very steep learning curve. As John mentioned, it is rather primitive, which makes for a great advantage for amateur users who need to manage databases.

Source:

[1] Weiberg, Groff, Oppel, Davenport, SQL: The complete Reference, 2010, 3rd Ed.