DML

Data Manipulation Language

SQL subset for changing data -- INSERT, UPDATE, DELETE.

When you'd see it: Everyday database work. DML is the SQL for changing the data itself.

Why it matters: DML is the subset of SQL that changes data: INSERT, UPDATE, DELETE. An UPDATE or DELETE without the right WHERE clause is one of the classic ways to wreck a production database.

Common mistakes: Running an UPDATE or DELETE without a WHERE clause, or outside a transaction. It changes every row, and there is often no undo.