Starts at 1:16:19 in this video — Dimensional modeling + SCD in the SQL Warehouse course
Star schema
A fact (measures at a declared grain, e.g. one row per order line) plus denormalized dimensions (date, customer, product). Analysts join on keys. This is the default BI model.
Snowflake
Dimensions are normalized into more tables (product → category). More joins, less duplication. Use when dimensions are large and shared.
Grain and SCD
Write the grain in a comment. Type 1 overwrites attributes; Type 2 adds a row with effective dates. “Customer segment as of order date” needs Type 2 (or a snapshot), not the current customer row.
The 3h course walks star schema and Type 2 SCD in Databricks SQL — watch from 1:16.