SQL(Structured Query Language)
The Structured Query Language (SQL) is a standard programming language to access
and manipulate databases. SQL allows the user to create, retrieve, alter, and transfer information
among databases. It is a language designed for managing and accessing data in a Relational
Data Base Management System (RDBMS)
The various processing skills of SQL are :
- DML – Data Manipulation Language:
- DDL – Data Definition Language:
- DCL – Data Control Language:
- TCL – Transaction Control Language:
- DQL – Data Query Language:
DATA DEFINITION LANGUAGE
The Data Definition Language (DDL) consist of SQL statements used to define the
database structure or scheme
- Create: To create tables in the database.
- Alter: Alters the structure of the database.
- Drop: Delete tables from database.
- Truncate: Remove all records from a table, also release the space occupied by those records.
DATA MANIPULATION LANGUAGE
A Data Manipulation Language (DML) is a computer programming language used
for adding (inserting), removing (deleting), and modifying (updating) data in a database.
- Insert: Inserts data into a table
- Update: Updates the existing data within a table.
- Delete: Deletes all records from a table, but not the space occupied by them
DATA CONTROL LANGUAGE
A Data Control Language (DCL) is a programming language used to control
the access of data stored in a database.
- Grant: Grants permission to one or more users to perform specific tasks.
- Revoke: Withdraws the access permission given by the GRANT statement
TRANSACTIONAL CONTROL LANGUAGE
Transactional control language (TCL) commands are used to manage transactions
in the database.
- Commit : Saves any transaction into the database permanently.
- Roll : back Restores the database to last commit state.
- Save : point Temporarily save a transaction so that you can rollback.
DATA QUERY LANGUAGE
The Data Query Language consist of commands used to query or retrieve data from a
database
- Select : It displays the records from the table.
Let’s see each commands now,