Friday, October 2, 2009

Introduction to SQL

Structured Query Language (SQL) is the standard language, designated to access and manipulate relational databases.

SQL pronounced “sequel” or as the letters “S-Q-L.”

SQL uses a simple syntax. There are five types of SQL statements as outlined below:

  • Query statements
Retrieve rows stored in database table by writing a query using the SELECT statement.
  • Data Manipulation Language (DML) statements

Insert, Update and Delete rows in a database table.

  • Data Definition Language (DDL statements

Create, Alter and Drop a database structure, Rename a table name and Truncate allows the deletion of the entire contents of the table

  • Transactional Control (TC) statements
  • Data Control Language (DCL) statements