Data Warehouse Model Design Workflow
Design a dimensional model for a data warehouse with fact and dimension tables optimized for analytical queries.
Objective
Design a star schema data warehouse model for efficient analytics.
Environment
- Source data and business requirements
- A data warehouse platform
- Understanding of dimensional modeling
Steps
1. Identify facts
Determine the business processes that need measurement (sales, clicks, shipments).
Expected state: Fact tables are identified for each business process.
2. Identify dimensions
Define the descriptive attributes for each fact (time, product, customer, geography).
Expected state: Dimension tables are defined with attributes and hierarchies.
3. Choose grain
Select the most granular level of data for each fact table.
Expected state: The grain is chosen and documented for each fact.
4. Design keys
Choose between surrogate and natural keys for dimension tables.
Expected state: Key strategy is documented for each table.
5. Validate with queries
Test the model against representative analytical queries for performance and simplicity.
Expected state: The model supports the required analytical queries efficiently.
Decision points
Star or snowflake schema?
- Star for performance
- Snowflake for storage
Use star schema for query performance; snowflake only when storage is a primary concern.
Expected outcome
A dimensional data warehouse model is designed and validated against business requirements.
Verification
Run representative queries against the model and confirm they return correct results with good performance.
Cleanup
Revise the model if queries are slow or do not match business requirements.
Dimensional modeling for humans
A well-designed dimensional model makes business queries simple to write and fast to run.
Implementation Notes
This workflow provides a structured approach to ensure consistent results across team members and environments.
Common Pitfalls
Skipping verification steps or rushing through the process can lead to incomplete results. Always follow each step in order and verify before proceeding.
Quick Reference
# Execute the workflow steps as documented above
echo "Workflow completed successfully"