NormalisationThe first three normal forms, in the order you apply them.ComputingEach form assumes the previous one is already satisfied.11NF — atomic valuesNo repeating groups, no comma-separated lists in a column. Onevalue per cell.22NF — full dependency on the keyNo column depends on only part of a composite primary key.33NF — no transitive dependencyNo column depends on another non-key column.4Then denormalise deliberatelyDuplicate data only for a measured read performance need.3NF VIOLATIONorders(id, customer_id, customer_city)city depends on customer, not on the orderMove it to the customers tableEvery duplicated fact is a chance for two copies to disagree. That, notdisk space, is what normalisation prevents.Normalisationlearnposters.com
Normalisation — printable computing wall chart from LearnPosters. Free vector PDF, US Letter and A4.

Normalisation, step by step

Each form assumes the previous one is already satisfied.

  1. 1NF — atomic valuesNo repeating groups, no comma-separated lists in a column. One value per cell.
  2. 2NF — full dependency on the keyNo column depends on only part of a composite primary key.
  3. 3NF — no transitive dependencyNo column depends on another non-key column.
  4. Then denormalise deliberatelyDuplicate data only for a measured read performance need.

3NF violation

  • orders(id, customer_id, customer_city)
  • city depends on customer, not on the order
  • Move it to the customers table

Every duplicated fact is a chance for two copies to disagree. That, not disk space, is what normalisation prevents.

Questions about the Normalisation poster

What’s on the Normalisation poster?
4 numbered steps, with a full worked run-through. Each form assumes the previous one is already satisfied. 1NF — atomic values — No repeating groups, no comma-separated lists in a column. One…; 2NF — full dependency on the key — No column depends on only part of a composite prim…; 3NF — no transitive dependency — No column depends on another non-key column.; Then denormalise deliberately — Duplicate data only for a measured read performance n…. Every duplicated fact is a chance for two copies to disagree. That, not disk space, is what normalisation prevents.
Who is the Normalisation poster for?
Normalisation belongs to the Computing section rather than to a school year, because computing is not something one grade owns. Anyone learning data can pin it up — a beginner, a student mid-course, or someone revising years later.
When should you use the Normalisation poster?
Normalise until it hurts, denormalise until it works. Start normalised; you can always undo it. A wall chart earns its place by being glanceable from where the work is happening, so Normalisation belongs on the wall where that computing work actually happens, within glancing distance, rather than filed away.
What other posters go with Normalisation?
ACID, The CAP Theorem and Choosing a Chart sit alongside Normalisation in the Computing section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.ACIDThe CAP TheoremChoosing a Chart
Is the Normalisation poster free to download and print?
Yes. Normalisation downloads as a free PDF with no account, no email and no watermark, like everything else in the Computing section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
What size does the Normalisation poster print at?
Normalisation is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Normalisation loses nothing.Printing guide

Related posters

Charts that sit alongside Normalisation on the same wall.

Browse every Computing poster, or start from the full catalogue.