
Explanation:
Box 1: One-to-many
Box 2: Many-to-one
In a star schema, the fact table (OrderHistory) sits in the center, and the dimension tables (Products, Date) connect to it.
- Products → OrderHistory:
Products[ProductID] is a dimension key with unique values.
OrderHistory[ProductID] is a foreign key that can repeat many times (since many orders can reference the same product).
- OrderHistory → Date:
Date[Date] is unique in the Date dimension (each calendar date appears once).
OrderHistory[OrderDate] can repeat many times (many orders on the same date).