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SQL: Adding and Editing Data

FoundationHigherAQA

Practise SQL: Adding and Editing Data for GCSE Computer Science with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA GCSE Computer Science (8525). Records are changed using INSERT to add, UPDATE to edit and DELETE to remove data.

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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA specification. Every worksheet comes with a full mark scheme.

Foundation

WorksheetFoundation · PDFMark SchemeFoundation · PDF

Higher

WorksheetHigher · PDFMark SchemeHigher · PDF

Topic overview

Three SQL statements modify data rather than retrieving it: INSERT adds records, UPDATE changes them, and DELETE removes them.

INSERT INTO names the table and fields, then VALUES supplies the data. Text values need quotation marks and the values must match the fields in order.

UPDATE names the table, SET states the change, and WHERE identifies which records to change. DELETE FROM removes records matching a WHERE condition. The critical point is that omitting WHERE from an UPDATE changes every record in the table, and omitting it from a DELETE removes every record — both irreversible without a backup. Checking the WHERE clause before running either is the habit worth building.

Revision notes

INSERT

INSERT INTO names the table and the fields, and VALUES supplies the data.

INSERT INTO Students (Name, Age) VALUES ('Amir', 15). Text needs quotation marks; the values must match the fields in order.

UPDATE

UPDATE names the table, SET states the change, WHERE identifies which records.

UPDATE Students SET Age = 16 WHERE StudentID = 3 changes one record. Without the WHERE clause, every record in the table would be changed.

DELETE and the WHERE warning

DELETE FROM Students WHERE StudentID = 3 removes one record.

DELETE FROM Students with no WHERE clause removes every record in the table. The same applies to UPDATE. Both are irreversible without a backup, so the WHERE clause should always be checked before running.

Key points

  • INSERT adds new records.
  • UPDATE changes existing records.
  • DELETE removes records.
  • VALUES must match the fields in order.
  • UPDATE without WHERE changes every record.
  • DELETE without WHERE removes every record.

Worked examples

Example 1

Write an SQL statement adding a record with Name 'Amir' and Age 15 to Students. [3 marks]

Working

INSERT INTO Students (Name, Age)name the table and the fields
VALUES ('Amir', 15)supply the values in matching order
Text is quoted and the number is notapply the correct quoting

Example 2

Write a statement changing the Age to 16 for the student with StudentID 3. [3 marks]

Working

UPDATE Studentsname the table
SET Age = 16state the change
WHERE StudentID = 3identify which record to change

Example 3

Explain why omitting the WHERE clause from a DELETE statement is dangerous. [2 marks]

Working

Without WHERE, the statement applies to every record in the tablestate what happens
so all the data is removed, and this cannot be undone without a backupexplain the consequence

Common mistakes

  • Omitting WHERE from UPDATE or DELETE.

    Every record in the table is affected.

  • Mismatching fields and values.

    They must correspond in order and in number.

  • Quoting numbers.

    Only text values need quotation marks.

  • Confusing UPDATE with INSERT.

    INSERT adds a new record; UPDATE changes an existing one.

Exam tips

  • Always include a WHERE clause on UPDATE and DELETE.
  • Match values to fields in order.
  • Quote text but not numbers.
  • Check the WHERE clause before running the statement.

Key terms

INSERT
The statement adding a new record.
UPDATE
The statement changing existing records.
DELETE
The statement removing records.
SET
The clause stating what an UPDATE changes.

Related topics

Written and reviewed against the current AQA specification. Spotted an error? Let us know.