SQL called by sequel; the letters formerly stood for Structured Query Language, nevertheless by now the acronym is regularly used as the name was deployed in the 1970s by IBM. It has become the standard language used to interface to relational database management systems RDBMS and DBMS such as IBM’s own DB2 and SQL/DS products, Oracle, Microsoft SQL Server and Access. Sybase Adaptive Server Enterprise, Sybase SQL Anywhere, Computer Associates’ Ingres, Informix, MySQL, mSQL, First SQL, and others. It is safe to say that if you are going to use relational databases in the near future, you will be working with SQL.
Typically, a relational database product includes more than just the DBMS. The DBMS; occasionally called the “back end”, the database engine, or even merely the server, though the term is also used in a more universal intelligence. It stores the data and retrieves or updates it in response to SQL statements. In a client/server environment, the DBMS typically resides on the server. In an internet or Intranet environment, it will typically be accessed by the web server, constituting a three-tiered architecture (the tiers being the browser, the Web server, and the database). There may be any number of additional layers in addition to those three.
Also, relational product usually provide various front end or middle ware tools that make it easier to communicate with the back end and provide you with facilities to use the data that you have retrieved. Among the tools you may encounter are forms, report generators, fourth generation languages (4GLs), graphical query languages, user-interface generators, multimedia presentation software, hypertext authoring systems, CAD/CAM systems, spreadsheets, and good, old-fashioned, direct-to-user interfaces. All of these practice SQL to demand the DBMS to accomplish several actions. The DBMS is in charge of storing, organizing, and retrieving the data, ensuring its integrity, protecting security, and keeping simultaneous users of the data from interfering with each other. We need to focus here is on how the front end must interface to the back end, rather than on the nature of the front-end tools or on the details of how the back end is actually implemented.