DDL and DML with Examples:

DDL (Data Definition Language): Defines/modifies schema structure. Auto-commit, no rollback. Commands:

• CREATE TABLE Student(roll INT PRIMARY KEY, name VARCHAR(50));
• ALTER TABLE Student ADD age INT;
• DROP TABLE Student;
• TRUNCATE TABLE Student;
• CREATE INDEX idx_name ON Student(name);

DML (Data Manipulation Language): Manipulates data within structures. Needs COMMIT. Commands:

• SELECT * FROM Student WHERE age >20;
• INSERT INTO Student VALUES(1,'Amit',21);
• UPDATE Student SET age=22 WHERE roll=1;
• DELETE FROM Student WHERE roll=1;

DDL acts on metadata, DML on instances. DDL changes schema, DML queries/modifies rows.