3 Defining the Business and Logical Models

Designing the Conceptual Model Phase I: Functional and Nonfunctional Requirements

Design Challenges Query requirements Data restructuring Response times Managing data volumes Operating costs and interfaces Controlling interfaces and tools Backup and restore

Business Modeling Performing strategic analysis Creating the business model Creating the metadata

Performing Strategic Analysis Identify crucial business processes/areas Understand business processes Prioritize and select business processes to implement

Doing Your Homework Determine a compelling business motivation for building the warehouse Read the company annual report Collect pertinent external marketing literature Investigate earlier data warehousing attempts Evaluate the feasibility of adding necessary hardware

Recognizing Critical Success Factors Focus on the business Determine who your sponsors are for the internal business plan and forge strategic alliances with their business units Use an iterative methodology with a short deliverables time frame

Understanding Business Imperatives Seek a competitive advantage Track competitors Satisfy customers React to market changes quickly Adapt to change Access source data using query tools Aid decision making

Understanding Business Operations Event – activity that happens repeatedly Status – a condition of an object at a particular point in time Level – a quantitative measurement of an object at a particular point in time Roles – who, whom and what involved in the event

Developing Strategic Questionnaires Why do you need a data warehouse? What specific problem are you trying to solve? What are your objectives? What are the available resources? How will the results be measured?

Creating the Business Model Defining business requirements Determining granularity Documenting metadata

Existing metadata Production ERD model Interviews with business users Research Establishing Business Requirements Primary input Secondary inputs

Gathering Business Information Requirements How does your department measure success and how often? Describe your products (and other key business dimensions). Is there a natural way to categorize or group these? What type of routine analysis do you currently perform? What essential reports do you use?

Gathering IT Information Requirements Where is the data located today? On what systems? What is the format of the data? How often is the data refreshed? How volatile is the data? How is the data accessed today? What is the quality of the data?

When Do You Say No? Operational systems Operational data stores Daily updates

The Importance of Business Requirements Business requirements determine: The data that must be stored in the warehouse to answer business questions How the data is organized How often data is updated End-user application templates Maintenance and growth plans

Identifying Potential Business Processes Sample business processes: Regional store-front sales Internet sales Promotions Warehousing Shipping

Defining Functional Requirements No.RequirementPriority 1. The business users need to be able to analyze "product sales" over time by geographic area, by customer demographic, by stores and sales territory, and by product hierarchy. Also need to know the revenues, the costs and the margin in U.S. dollars. High 2. Need to be able to analyze "subscription sales" over time by geographic area, by customer demographic, by stores and sales territory, and by product hierarchy. HIgh …… …… Determine what features and functions of the data warehouse. What does the system do?

Defining Nonfunctional Requirements No.Requirement 1. All data warehouse users must be able to access the data warehouse front-end application without logging in again. 2. All front-end applications are ideally web-based, accessible from anywhere within the company network. …… …… Provide guides and constraints to the system architecture.

Conducting a Data Feasibility Study Explore the source system, to understand the data by listing the risk and verifying them whether it is possible to deliver the project as per the requirements. No.Risk 1. It is impossible to do data extraction from the source in one- hour limitation as specify in nonfunctional requirements. 2. We do not have the data in the source systems as specify in the functional requirements. …… ……

Examining the Business Processes/Areas Example : A product sales event happens when a customer is buying a product. Roles – customer, product and store Levels – (in dimensional modeling terms, the measures) are quantity, unit price, value, unit cost Put Roles in the dimension and Measures in the fact Events – the fact table

Examining the Business Processes/Areas Categorize business (processes perceived as constant or discrete): Product Date Customer (Person and Organization) Channel Promotions Success metrics (vary continuously): Units sold Cost Sales Margin Business Dimensions Measures

Using the Business Process Matrix Sample of business process matrix Business Dimension SalesReturns Successful Promotions CustomerXX DateXXX ProductXXX ChannelXX PromotionXXX Business Process

Selecting the Business Process Which will provide the best ROI? Which will provide the greatest strategic value? What kinds of business decisions can you make with this information? Which will be the easiest to implement in terms of human resources? How long will it take to implement this business process?

Granularity and Business Dimensions Product category? Product class? Product family? Product tier? Product item?

Measures and Key Reports

Documenting Business Model Elements For the selected business processes, the following business model elements should be documented: A list of the business measures Detailed lists for each business dimension Business definitions and rules

Identifying Business Definitions and Rules Credit Rating Meaning A+0 bad checks or bank credit failures A1 bad check or bank credit failures B2 bad checks or bank credit failures C3 or more bad checks or bank credit failures Customer Rule 1 A customer with a credit rating of A or above will receive a 10% discount on any order totaling $500 (U.S.) or more Rule 2 A customer with a credit rating of A or above will receive a 5% discount on any order totaling $250 (U.S.) but less than $500 … Rule 5 A customer with a credit rating of C will not receive any discounts on purchases Order …

Documenting Business Measures Current Increment Sales Cost Discount Margin Sales amount Channel Units Future Increments Promotions Type Description Suppliers Name Address Contact name

Please note that this is not an all-inclusive list Documenting Business Dimensions HistoryProductSalesOrderCustomer Date Day Month Quarter Cost Discount Margin Sales_Units Name Type Credit_Rating Address Year Day_Desc Product_Name Category Type Code Promotion_Code Warehouse_Loc Item_Nbr Item_Desc Quantity Discount_Price Unit_Price Order_Amount Quarter_Day_Desc Month_Day_Desc Year_Day_Desc

Creating the Metadata Metadata should: Document the design process Document the development process Provide a record of changes Record enhancements over time

Types of Metadata Warehouse Metadata repository Operational ETL Business (End-user)

Metadata Documentation Approaches Automated –Data modeling tools –ETL tools –End-user tools Manual

Business Metadata Elements Name of the measure Business dimension Dimension attribute Sample data Business definition and rules

Designing the Logical Model Phase II: Defining the logical model

Entity Relationship Modeling Bottom-up approach Transaction processing 3rd Normal Form

Order Customer * Name * Street * City… Entity Attribute Relationship Entity Relationship Diagram Entity relationship diagram (ERD) components

Relationships Link Entities Each ORDER must be for one and only one customer. Each CUSTOMER may be the initiator of one or more orders. Order Customer For The initiator of