DDL vs DML: Understanding the Two Core Categories of SQL Commands

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SQL commands are broadly divided into two categories: Data Definition Language (DDL) and Data Manipulation Language (DML). DDL commands such as CREATE, ALTER, and DROP are used to build and modify the structure of a database, including its tables and schemas. DML commands such as INSERT, UPDATE, DELETE, and SELECT operate on the data stored within those structures. The distinction can be thought of as construction versus operation — DDL sets up the database, while DML handles day-to-day data interactions. Grasping this difference helps developers navigate SQL more confidently and reduces common confusion around command usage.

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