In 1971, IBM research workers created a straightforward non-procedural dialect called Structured English Query Language or SEQUEL. This is predicated on Dr. Edgar F. (Ted) Codd's design of a relational model for data storage space where he defined a universal program writing language for accessing directories.

In the later 80's ANSI and ISO (they are two organizations working with requirements for a multitude of things) arrived with a standardized version called Structured Query Language or SQL. SQL is pronounced as 'Sequel'. There were several editions of SQL and the latest some may be SQL-99. Though SQL-92 is the existing universally implemented standard.

SQL is the terminology used to query all directories. It's easy to learn and seems to do hardly any but is the heart and soul of an effective database program. Understanding SQL and deploying it proficiently is highly important in designing a competent database request. The better your knowledge of SQL the greater versatile you will be in getting information out of directories.