These commands are basically known as the way of communication or instruction to the database engine. Let’s starts with the explanation.
DDL: [Data Definition Language]
• CREATE, ALTER, DROP, TRUNCATE AND RENAME
• These above commands are needed to do an exclusive lock on the object being acted upon.
DML: [Data Manipulation Language]
• SELECT, INSERT, UPDATE, DELETE, MERGE or UPSERT
• These are the commands used to do manipulation within schema objects
DCL: [Data Control Language]
• GRANT and REVOKE
• These are a kind of commands used to create roles, permissions and managing the data security.
TCL: [Transaction Control Language]
• BEGIN TRAN, COMMIT TRAN, ROLLBACK and SET TRANSACTION
• These are a kind of commands used to control the change made by DML statements. Also it consolidates multiple logical statements into a single group.