COURSE 16 OF 22
Data Modeling and Warehouses
Choose what each row means, preserve history, and build tables people can trust.
Background reading
Introduction to Data Modeling and Warehouses
A courier company asks: how much delivery revenue did each city earn yesterday? Before choosing a database, ask what counts as revenue. Does a cancelled delivery count? Which date matters when a delivery crosses midnight?
Start with one delivery. Its identifier, completion time, city and charge describe one business event. A table with one row per completed delivery has a clear grain: the meaning of a single row. Every measure in that table must belong to that same grain.
Loading course…