DML stands for Data Manipulation Language. DDL: DDL is Data Definition Language which is used to define data structures. SQL | DDL, DQL, DML, DCL and TCL Commands. 5 days ago · What is DDL? Data Definition Language helps you to define the database structure or schema. The basic difference between DDL and DML is that DDL (Data Definition Language) is used to Specify the database schema database. SQL comes with standard commands to interact with the RDBMS.