Core Concepts
Fact Tables
Fact tables store quantitative measurements of business processes. They contain the metrics that business users want to analyze.
Characteristics:
- Contain numeric, additive measures
- Foreign keys to dimension tables
- Large volume of records
- Sparse (many null values)
Example Measures:
Sales AmountQuantity SoldProfitDiscount
Dimension Tables
Dimension tables provide descriptive context for facts. They contain the "who, what, when, where, why, how" of business processes.
Characteristics:
- Contain textual, descriptive attributes
- Primary key referenced by fact tables
- Relatively small volume
- Dense (few null values)
Common Dimensions:
Date/TimeProductCustomerGeography
Interactive Exercise: Classify Attributes
Drag the attributes below into the correct category:
Available Attributes:
Sales Revenue
Customer Name
Quantity Ordered
Product Category
Store Location
Discount Amount
Facts (Measures)
Numeric, quantitative data
Dimensions (Attributes)
Descriptive, contextual data