Until now you have only read data, but real databases change constantly: new matches are recorded, scores are corrected, obsolete records are removed. The three Data Manipulation Language statements, INSERT, UPDATE, and DELETE, are how you write to a database. Together they let you add rows, change existing ones, and remove rows, turning a static dataset into a living system that reflects reality.
These statements are powerful precisely because they alter stored data permanently. A misplaced UPDATE can overwrite thousands of rows, and a DELETE without a WHERE clause can empty an entire table in an instant. That power demands discipline: a clear WHERE clause, an understanding of how many rows each statement affects, and the transactional safety net covered in the next lesson.
Mastering DML is the difference between querying a database and operating one. Applications insert on every signup, update on every edit, and delete on every removal, often thousands of times per second. Writing these statements correctly, targeting exactly the intended rows and respecting the table's constraints, is fundamental to keeping a database accurate, consistent, and trustworthy under constant change.