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OCR H446 1.3.2 First normal form

Part 3 of 13 · H446 1.3.2 · Databases

First normal form is the entry point to normalisation in H446 1.3.2, and this worksheet concentrates on spotting repeating groups and fields that hold several values at once. Students transform data into 1NF while checking that no fact has been lost on the way.

Students will:

  • identify repeating groups and fields holding more than one value
  • rewrite unnormalised rows so that each field holds a single value
  • choose a key that stays unique after the transformation
  • check that the transformed design still preserves every original fact
  • explain why the absence of repeating groups does not prove a relation is in 2NF or 3NF

Inside: 7 explanation cells, 2 multiple-choice questions, 2 fill-in-the-blanks cells and 3 written answers. 25 marks, about 25 to 35 minutes.

Series: H446 1.3.2 · Databases, part 3 of 13.

Shared by Coding PathwayVerified teacher

  • 14 cells
  • About 30 minutes
  • CC BY-SA 4.0
  • Shared 31 Aug 2026
  • Updated 3 Sept 2026

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The whole resource, exactly as a class sees it. Answers and marking are held back.

First normal form

Normalisation reorganises data into relations that reduce avoidable repetition and support reliable changes. First normal form (1NF) is the starting point.

By the end, you will be able to

  • identify repeating groups and non-atomic fields;
  • choose a key that uniquely identifies each 1NF row;
  • transform unnormalised data into 1NF;
  • explain why 1NF is necessary but does not guarantee 2NF or 3NF.

Reactivate: a key identifies a record; one field should store one value of the intended type.

One field, one value

From a repeating group to first normal formNot 1NFregistration_id: R14student_id: S08workshops: W2, W5, W9one field stores three valuesone workshop per row1NF relationregistration_idstudent_idworkshop_idR14S08W2R14S08W5R14S08W9The composite key (registration_id, workshop_id) identifies each row.

A value is atomic for the design when it cannot usefully be divided for the database task. The list W2, W5, W9 is not atomic because the system needs to search and link individual workshops.

The 1NF relation has one workshop per row and no repeating workshop columns. The composite key (registration_id, workshop_id) distinguishes the rows.

Worked transformation

Unnormalised:

booking_idcustomer_idevent_1event_2
B31C07E4E9

The event columns form a repeating group. A 1NF relation can instead store:

booking_idcustomer_idevent_id
B31C07E4
B31C07E9

A suitable key is (booking_id, event_id). This transformation reaches 1NF, but customer_id still repeats. Later normal forms consider dependencies, not merely repeated values.

Multiple choice1 mark

Which change is required to place the workshop list in 1NF?

  • AStore every workshop code in one longer text field
  • BStore one workshop code per row and identify each row
  • CCreate extra columns workshop_1, workshop_2 and workshop_3
  • DEncrypt the workshop codes before storing them
Multiple choice1 mark

A DateAccessed field stores '03/06, 10/06, 22/06' in one row. What is the most direct 1NF problem?

  • AThe field contains a repeating group/non-atomic list of dates
  • BThe table necessarily has too many foreign keys
  • CThe database has not implemented record locking
  • DAny repeated date anywhere violates 3NF
Fill in the blanks3 marks
A relation in 1NF has no gap 1, stores gap 2 values in each field for its purpose, and has a key that gap 3 each record.
  • repeating groups
  • foreign tables
  • atomic
  • encrypted
  • uniquely identifies

Guided checkpoint: repair a contact list

VOLUNTEER(volunteer_id, name, phone_numbers)

Record V12 stores phone_numbers as 07111 111111, 07222 222222. The organisation must search each number separately.

Plan: locate the multi-value field → make one phone value appear in each row → choose a key that still distinguishes rows → state what has and has not been solved.

Written answer5 marks

Write a 1NF design for the volunteer phone data and state its primary key.

A separate VolunteerPhone relation is one valid answer.

Students type their answer here.

Written answer3 marks

Explain why saying only 'there are no repeating groups' does not prove that a relation is in 2NF or 3NF.

Refer to the different dependency tests introduced next.

Students type their answer here.

Independent transfer: course choices

A record is stored as STUDENT_CHOICE(student_id, student_name, subjects), where subjects contains values such as Computer Science, Mathematics, Physics in one field. Each subject must be searchable.

Written answer8 marks

Transform the course-choice data to 1NF. Show example rows for student S15 choosing three subjects, state a suitable key and explain two changes you made.

Do not jump straight to 2NF unless you clearly show the 1NF relation first.

Students type their answer here.

Closed-book checkpoint

Complete each sentence from memory. There is no answer bank and correctness is held for teacher review.

Fill in the blanks4 marks
First normal form stores one value for the field's purpose in each completion 1. Repeated items become separate completion 2. More than one field may form a completion 3 key. The transformation must retain every original completion 4.

Review your understanding

Before submitting, check that you can explain the main distinction in your own words, apply it in an unfamiliar context and justify each consequence rather than only naming a feature.