The big idea: SQL does two quite different things, and the exam names them separately.
DDL builds the containers — the tables and columns themselves. DML puts things into those containers and takes them out again.
The test: Ask: does this statement change the shape of the database, or its contents?
Shape is DDL. Contents is DML.
Free preview
This is the free notes preview
You're reading the free notes. Aimnova Pro unlocks the full study experience — and you can try it with your first topic free to keep:
- FlashcardsLock in vocabulary and key terms with spaced repetition.
- Practice questionsAnswer exam-style questions and get instant AI marking.
- Mock exams & past-paper vaultSit full mocks and see exactly how examiners award marks.
- Personalised study planA daily plan built around your exam date and weak areas.
Start Studying Free Full access to Aimnova Pro · cancel anytime
Data definition language: DDL statements create, change and remove the structures that hold data — tables, columns, keys, indexes.
They are run rarely: when the database is first built, and when its design genuinely changes.
CREATE
- Makes a new table, with its columns and types
- Where PRIMARY KEY and FOREIGN KEY are declared
- Also used for indexes and whole databases
ALTER
- Changes an existing structure
- Adds, removes or changes a column
- Slow and disruptive on a table with millions of rows
DROP
- Removes a table, and everything in it
- Not the same as deleting rows — the table itself is gone
- There is no undo
Stop wasting time on topics you know
Our AI identifies your weak areas and focuses your study time where it matters. No more overstudying easy topics.
Try Smart Study FreeYour first topic is free to keep • No credit card required
Data manipulation language: DML statements read and change the rows inside tables that already exist.
These are the statements a running application uses, thousands of times a day.
DELETE and DROP are not the same: DELETE removes rows; the table stays, ready for more.
DROP removes the table itself, with its structure and all its data. Confusing them is the most expensive mistake in this topic.
Who runs which: DDL is usually run by a database administrator, occasionally, under supervision.
DML is run by the application, constantly. That difference is often what a question is really about.
How this is tested — you must classify a statement and say what it acts on — structure or rows. It comes up two ways:
Paper 1 Section A
- Outline the difference between DDL and DML, 2-3 marks
- Classify given SQL statements
- Name a statement belonging to each
Paper 1 Section B — case study
- Identify the SQL the case study would need
- Say who would run each kind, and when
The classic trap: Putting DELETE with DROP because both remove things. DELETE is DML — it removes rows from a table that stays. DROP is DDL and removes the table itself.
IB-style questionOutline[4 marks]
Outline the difference between DDL and DML, giving two examples of each and saying who would typically run them.
Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.