Every SQL command falls into a handful of categories, and two of the most fundamental are DDL (Data Definition Language) and DML (Data Manipulation Language). One defines the structure your data lives in. The other works with the data itself. Once that distinction clicks, the rest of SQL starts falling into place. What is DDL? DDL, or Data Definition Language, is the set of SQL commands used to define, modify, and remove the structure of database objects such as tables, schemas, ...