Lesson 03 of 7 · Facts and dimensions
Things that happened. Things you describe them by.
A fact table records what happened. A dimension describes it. Get that split right and every slicer just works.
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Two kinds of table
A fact table records things that happened: a month of trade, a year of prices, a facility's capacity. Its columns are keys and numbers you add up. A dimension describes those things: which commodity, which country, which date. Its columns are the words you slice and label by.
The model has 8 dimensions, and every fact table points at the ones it needs through a key.
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Fact or dimension? Decide where each column belongs.
Tonnes exported
Country name
Commodity group
Price per tonne
Month name
Facility capacity
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Explore one star
Fact tables are usually the long ones. Which has more rows in this model?
Answer the question above to unlock this.
Tables explored: 0 of 6
A simplified view: two fact tables and a few of the 53 relationships. The table names and row counts are the real ones.
The ruleNumbers you add up go in facts. Words you slice by go in dimensions. Facts carry keys, never the names themselves.