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

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

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

OLTP Entity Relationship Diagram

Information Package

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

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

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

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

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

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

Star Schema

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

Physical Design – Customer table Three classifications

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

Physical Design – Time table

Physical Design – SalesFact table

Any Questions?