Structured Query Language ( SQL )

Structured Query Language ( SQL ) is a set of specialized commands that are used to access data in a relational database . SQL is a computer language that follows the ANSI ( American National Standard Institute ) used in relational database management . With SQL , we can access the database , run a query to retrieve data from the database , add data to the database , delete data in the database , and change the data in the database . Today almost all the existing database server supports SQL to perform data management .

There are three (3 ) types of SQL commands , namely DDL , DML and DCL .

1 . DDL or Data Definition Language

DDL is a SQL command associated with the definition of a database structure , in this case the database and table . SQL commands are included in the DDL , among others :

CREATE

ALTER

RENAME

DROP

2 . DML or Data Manipulation Language

DML SQL commands that are associated with the manipulation or processing of data or records in a table . SQL commands are included in the DML , among others :

SELECT

INSERT

UPDATE

DELETE

3 . Data Control Language DCL or

DCL is the SQL command associated with setting user permissions , either on the server , database , table or field . SQL commands are included in the DCL , among others :

GRANT

REVOKE

SQL history starts from the article a researcher named EF Codd of IBM discussing the idea of ​​creating a relational database in June 1970. This article also discusses the possibility of making a standard language for accessing data in the database . The language was later given the name SEQUEL ( Structured English Query Language ) . After the publication of the article, IBM held a project of the SEQUEL language -based relational database . However , due to legal issues regarding the naming SEQUEL , IBM also turn it into SQL . Implementation of relational database known as System / R. In the late 1970s , emerging company called Oracle which makes popular database server named the same as the company name . With the rising popularity of Oracle , so SQL also popular that now the de facto standard language in database management .