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

… …  

… …  

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 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