Normalisation to Third Normal Form · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Split the tables until nothing can disagree

Computing · Computer Systems · ages 17-18
Name ______________________   Date ____________

  1. Normalisation is finished when every field depends on what?

    • The key, the whole key, and nothing but the key
    • The longest text in the row
    • The designer's favourite column

  2. What does first normal form require of every cell?

    • Several values packed together
    • Room for a small list
    • Exactly one value, no repeating groups

  3. Repeating the customer address on every order keeps the data safe.

    Circle one:   True   False

  4. You cannot add a new product without inventing a fake order. Which problem bites?

    • The insert problem
    • The spelling problem
    • The sorting problem

  5. An address changes and the update misses one order row. What is this called?

    • A sorting error
    • An update anomaly
    • A join error

  6. Deleting the last order for a product can wipe out that product entirely.

    Circle one:   True   False

  7. A designer repeats the customer city on every order to answer questions faster. What duty comes with it?

    • None, because speed fixes everything
    • Deleting the customer table at once
    • Guarding the copies so they stay in step

  8. A table uses order id plus product id as its key. The product name depends only on the product id. What is broken?

    • Nothing, because the name is spelled right
    • Second normal form, because a field ignores part of the key
    • First normal form, because a cell holds a list
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Split the tables until nothing can disagree W1-mt_cbRXVW6KxX-s1

  1. The key, the whole key, and nothing but the key · That old motto is the whole test in one line.
  2. Exactly one value, no repeating groups · One value per cell keeps every fact separate and countable.
  3. False · Copies drift apart, so the repetition creates danger instead of safety.
  4. The insert problem · The design blocks a new fact until you forge it a host row.
  5. An update anomaly · One fact changed in most places but not all, so the rows contradict each other.
  6. True · The product facts lived only on order rows, so they vanish with them.
  7. Guarding the copies so they stay in step · A deliberate repeat is a promise you must keep on every write.
  8. Second normal form, because a field ignores part of the key · The name follows half the key instead of the whole key.
Worksheet · LightMySky