What is SQL?

By | July 2, 2015


SQL is an ANSI (American National Standards Institute) standard computer language, which is used for storing, manipulating and retrieving data stored in relational database. SQL is the standard language for Relational Database System.


History

  • 1970: Dr.E. F. Codd of IBM (known as the father of relational database) has described a relational model for database.
  • 1974: Structured Query Language appeared.
  • 1978: IBM has worked to develop Codd’s ideas and released a product named System/R.
  • 1986: IBM has developed first prototype of relational database and standardized by ANSI. First relational database was released by Relational Software and its later becoming Oracle.

SQL Process

When executing an SQL commands, system first determines the best way to carry out SQL query request and SQL engine figure out how to interpret the task. There are various components included in the process which is known as Query Dispatcher, Optimization Engines, Classic Query Engine and SQL Query Engine etc. Classic Query engine handles all non-SQL queries, but SQL query engine won’t handle logical files. Figure: 1 shows simple diagram of SQL Architecture.

Figure-1 Diagram of SQL Architecture

Above diagram shows that when SQL Query will fire first Query Language Process parses and optimize sql query and pass the optimized version into the Database engine. Database engine uses transaction manager to retrieve information from the physical database.

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