History of SQL

Dr. E. F. Codd published the paper, "A Relational Model of Data for Large Shared Data Banks", in June 1970 in the Association of Computer Machinery (ACM) journal, Communications of the ACM. Codd's model is now accepted as the definitive model for relational database management systems (RDBMS). The language, Structured English Query Language (SEQUEL) was developed by IBM Corporation, Inc., to use Codd's model. SEQUEL later became SQL (still pronounced "sequel"). In 1979, Relational Software, Inc. (now Oracle) introduced the first commercially available implementation of SQL. Today, SQL is accepted as the standard RDBMS SQL Standard. ANSI (American National Standards Institute) and the ISO (International Standards Organization) /IEC (International Electro Technical Commission) have accepted SQL as the standard language for relational databases. When a new SQL standard is simultaneously published by these organizations, the names of the standards conform to conventions used by the organization, but the standards are technically identical. The latest SQL standard was adopted in July 1999 and is often called SQL:99.

Introduction of SQL

Structured Query Language (SQL) is the set of statements with which all programs and users access data in a database. SQL is the standard query language to fetch, modify, update & process the data in Relational Database Management System. Relational Database Management System A relational database is a database that is treated as a set of tables and manipulated in accordance with the relational model of data. It contains a set of objects used to store, manage, and access data. Examples of such objects are tables, views, indexes, functions, triggers, and packages. And the software used for Relational Database is known as Relational Database Management System.

How SQL Works

The strengths of SQL provide benefits for all types of users, including application programmers, database administrators, managers, and end users. The features of SQL are the following: It processes sets of data as groups rather than as individual units. It provides automatic navigation to the data. It uses statements that are complex and powerful individually, and that therefore stand alone. Flow-control statements were not part of SQL originally, but they are found in the recently accepted optional part of SQL, ISO/IEC 9075-5: 1996. Flow-control statements are commonly known as "persistent stored modules" (PSM), and the PL/SQL extension to Oracle SQL is similar to PSM. SQL provides statements for a variety of tasks, including: " Querying data " Inserting, updating, and deleting rows in a table " Creating, replacing, altering, and dropping objects " Controlling access to the database and its objects " Guaranteeing database consistency and integrity