DML - is abbreviation of Data Manipulation Language. It is used to retrieve, store, modify, delete, insert and update data in database.
e.g.: SELECT, UPDATE, INSERT statements
DDL - is abbreviation of Data Definition Language. It is used to create and modify the structure of database objects in database.
e.g.: CREATE, ALTER, DROP statements
DCL -is abbreviation of Data Control Language. It is used to create roles, permissions, and referential integrity as well it is used to control access to database by securing it.
e.g.: GRANT, REVOKE statements
TCL - is abbreviation of Transactional Control Language. It is used to manage different transactions occurring within a database.