SQL – Structured Query Language is further categorized on the basis of various commands and functionality types done by a particular set of keywords and the overall impact on a particular set of database objects. They are as follows:
- DDL – Data Definition Language
- DML – Data Manipulation Language
- DCL – Data Control Language
- DQL – Data Query Language
- TCL – Transactional Control Language
DDL
The Data Definition Language is used to create, modify or remove a particular database object. The keywords included in DDL are ‘Create’, ‘Alter’ and ‘Drop’. These keywords can be used to against tables, views, functions, stored procedures and other such objects.
DML
The Data Manipulation Language is used to add, modify or remove the content of a table. The keywords included in DML are ‘Insert’, ‘Update’ and ‘Delete’.
DCL
The Data Control Language is used for granting or revoking certain permissions to various users and roles mentioned in the database. It is used to create roles, permissions, and referential integrity as well it is used to control access to database by securing it. The ‘Grant’ and ‘Revoke’ are the primary keywords in DCL.
DQL
The Data Query Language is used to retrieve the data from a Table or a View. The ‘Select‘ keyword is used in DQL to access the data from a database object. It can be used in simple queries, views and stored procedures.
TCL
The Transactional Query Language is used to manage different transactions occurring within a database. The keywords include ‘Commit’, ‘Rollback’, ‘Save Transaction’, etc.
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Great for someone to remember