3 defining the business and logical models. designing the conceptual model phase i: functional and...
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3Defining 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 withbusiness 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. Requirement Priority
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
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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.
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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.
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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 Sales Returns
Successful Promotions
Customer X XDate X X XProduct X X XChannel X XPromotion X X X
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
January February MarchEurope
Channel - Internet
Product
Wine $8,500 $8,300 $10,900
Cheese 2,700 1,985 3,500Miscellaneous 850 300 950
Channel - Store-Front
Product
Wine $6,875 $5,800 $7,000
Cheese 550 450 600Miscellaneous 200 300 350
Channel - Internet
Product
Wine $4,700 $5,200 $7,400
Cheese 890 500 625Miscellaneous 850 225 650
Channel - Store-Front
Product
Wine $3,200 $3,075 $3,500
Cheese 250 350 275Miscellaneous 650 650 650
Country Sales Report
France
United Kingdom
Documenting Business Model Elements
For the selected business processes, the followingbusiness model elements should be documented:
• A list of the business measures
• Detailed lists for each business dimension
• Business definitions and rules
Identifying Business Definitionsand Rules
Credit Rating Meaning
A+ 0 bad checks or bank credit failuresA 1 bad check or bank credit failuresB 2 bad checks or bank credit failuresC 3 or more bad checks or bank credit failures
Customer
Rule 1A customer with a credit rating of A or above will receive a 10% discount on any order
totaling $500 (U.S.) or more
Rule 2A 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
History Product Sales Order Customer
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
Metadatarepository
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