2. Data Warehouse Project Star Schema and Physical Design
Presented by:
Mike Ellis Vinh Ngo

3. Today’s Agenda Business Definition review from 30,000 feet Star Schema
Physical Design

4. Type of Business Texas HVAC/R wholesaler 30 branch locations
Sell predominantly to licensed contractors, mostly on store accounts
16,000 line item products
700 active stocking
manufacturers

5. OLTP Entity Relationship Diagram

6. Information Package

7. Dimension Tables Product Store Time Customer ProductID (PK)
ProductName
Category
Subcategory
Store
StoreID (PK)
StoreName
StoreRegion
StoreState
StoreCity
StoreFootage
Time
TimeID(PK)
TimeDate
DateText
DayOfWeek
WeekDay
DayOfMonth
MonthNum
MonthText
Quarter
Season
Year
Customer
CustomerID (PK)
CompanyName
LicenseType
Size

8. Fact Table SalesFact ProductID (PK) TimeID (PK) StoreID (PK)
CustomerID (PK)
Quantity
PricePerUnit
CostPerUnit

9. Product Hierarchy Categories Subcategories
Each product is in one category and one subcategory only

10. Store Hierarchy Each store location is in one region Regions
South Texas
Central Texas
North Texas
Gulf Coast
Rio Grande Valley
Panhandle

11. Customer Hierarchy
Each customer is in each of the three classifications
Size
Small (1-3 techs)
Medium (4-10 techs)
Large (11–20 techs)
Corporate (21+ techs)
License Type
“A” license (HVAC and refrigeration)
“B” license (HVAC only)
Category
HVAC
Builder
Government
Refrigeration
Maintenance

12. Time Hierarchy Season Values Time Dimension Table TimeID(PK) TimeDate
DateText
DayOfWeek
WeekDay
DayOfMonth
MonthNum
MonthText
Quarter
Season
Year
Season Values
Winter
December
January
February
Spring
March
April
May
Summer
June
July
August
Fall
September
October
November

13. Star Schema

14. Physical Design – Product table
Part numbers with embedded information changed to integer ProductID
Category and Subcategory values

15. Physical Design – Customer table
Three classifications

16. Physical Design – Store table
Store Region values
Can also rollup by city

17. Physical Design – Time table

18. Physical Design – SalesFact table

19. Any Questions?