Information Systems Analysis and Design

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Information SystemsAnalysis and Design

• Lê Ng?c Ti?n
• http//tienhuong.wordpress.com

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Outline

1. Information Systems the big picture
2. Information Systems for competitive advantage
3. Organizational Information Systems
4. Entreprise-Wide Information Systems
5. Information Systems Development Acquisition
6. Managing the Information Systems Project
7. Systems Planning
8. Determining System Requirements
9. Structuring System Requirements Process
   Modeling
10. Structuring System Requirements Conceptual Data
    Modeling
11. Object Oriented Analysis and Design
12. Designing the Human Interface
13. Systems Implementation and Operation

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Chapter 1Information SystemsThe Big Picture
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Chapter 1 Objectives

• Understand the term information systems (IS)
• Understand IS components
• Technology, people, organizations
• Understand IS career opportunities
• Understand types of information systems
• Understand IS and organizational success or
  failure
• Understand the future of IS management

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Information Systems Defined

• Combinations of hardware, software, and
  telecommunications networks that people build and
  use to collect, create, and distribute useful
  data in organizations

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Key Elements of Information Systems
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Data

• Data raw material, unformatted information
• Information processed data (meaningful)
• Knowledge understanding relationships between
  pieces of information
• Wisdom knowledge accumulated and applied

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Knowledge as a Business Resource

• Knowledge Worker
• A well-educated professional who creates,
  modifies, or synthesizes knowledge in ones
  profession
• Knowledge Society
• Also called digital society, new economy
• Working with brains instead of hands
• The importance of education
• Digital divide

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Technology and Information Systems

• Computer-Based Information Systems
• One type of technology
• Technology any mechanical and/or electrical
  means to supplement, extend, or replace human
  activity
• Information Technology (IT) machine technology
  controlled by or using information
• The goal of IS is to provide useful data to users
• IS can be local or global, organizational or
  enterprise-wide

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IS Managerial Personnel

• CIO
• IS director
• Account Executive
• Info Center Manager
• Development Manager
• Project Manager
• Maintenance Manager
• Systems Manager
• IS planning Manager
• Operations Manager
• Programming Manager

• Systems Programming Manager
• Manager of Emerging Technologies
• Telecommunications Manager
• Network Manager
• Database Administrator
• Auditing or Computer Security Manager
• Quality Assurance Manager
• Webmaster

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Integrating Skills and Knowledge

• Technology
• hardware, software, networking
• Business
• business, management, social, communications
• Systems
• Integration, development methods, critical
  thinking, problem solving

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Hot Skills in IS Workers

• Office / E-mail
• Languages
• Applications
• RDBS Administration
• Development Tools
• Internetworking
• Operating Systems
• LAN Administration
• Networking

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IS Within the Firm

• Traditionally a love/hate relationship
• Techies vs. mere users (us vs. them)
• Poor service, lousy attitudes
• Now progress toward better customer service
• Better relationships within the company
• Cooperation, not rivalry

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The Spread of Technology in Organizations

• Technology infiltrates business units
• Dual role for IS workers
• Work with IS technical group
• Work with business unit (marketing, finance, etc.)

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The Spread of Technology in Organizations

• Benefits of centralized IS function
• Coordinated planning
• Consistent management
• Systems compatibility and connectivity

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Questions

• Define and understand the term information
  systems (IS)
• Explain the technology, people, and
  organizational components of an information
  system.

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Chapter 2Information Systems for Competitive
Advantage
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Chapter 2 Objectives

• Understand the IS in automation, organizational
  learning, and strategic support
• Understand IS for strategic organizational
  success
• Understand the need for making an IS business
  case
• Understand technological innovations to improve
  competitive advantage

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Why Use Information Systems?

• Automating doing things faster
• Organizational learning doing things better
• Supporting Strategy doing things smarter

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Automating Doing Things Faster

• Technology is used to automate a manual process
• Doing things faster, better, cheaper
• Greater accuracy and consistency
• Loan application example
• Manual processing
• Technology-supported process
• Completely automated

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Organizational Learning Doing Things Better

• Going beyond automation
• Involves learning to improve the day-to-day
  activities within the process
• Looking at patterns and trends
• Organizational Learning
• Using acquired knowledge and insights to improve
  organizational behavior
• Total Quality Management (TQM)
• Monitoring an organization to improve quality of
  operations, products, and services

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Supporting Strategy Doing Things Smarter

• Strategic Planning
• Create a vision setting the direction
• Create a standard performance targets
• Create a strategy reaching the goal

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Question

• Now, it should be fairly obvious why an IS
  professional should be able to make a business
  case for a given system. Why, however, is it just
  as important for non-IS professionals? How are
  they involved in this process? What is their role
  in information systems planning?

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Chapter 3OrganizationalInformation Systems
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Chapter Objectives

• Understand characteristics of operational,
  managerial, and executive information systems
• Understand characteristics of transaction
  processing systems, management information
  systems, and executive information systems
• Understand characteristics of information systems
  that span organizational boundaries

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Decision-Making Levels of an Organization
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Decision-Making Levels of an Organization

• Executive level (top)
• Long-term decisions
• Unstructured decisions
• Managerial level (middle)
• Decisions covering weeks and months
• Semistructured decisions
• Operational level (bottom)
• Day-to-day decisions
• Structured decisions

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General Types of Information Systems

• Transaction Processing Systems (TPSs)
• Transactions
• Used at Operational level of the organization
• Goal to automate repetitive information
  processing activities
• Increase speed
• Increase accuracy
• Greater efficiency

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General Types of Information Systems

• Data input
• Manual data entry
• Semiautomated data entry
• Fully automated data entry
• Examples
• Payroll
• Sales and ordering
• Inventory
• Purchasing, receiving, shipping
• Accounts payable and receivable

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General Types of Information Systems

• Management Information Systems (MISs)
• Two Types
• Management of IS in organizations
• Specific information systems for mid-level
  managers
• Used at managerial level of the organization

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General Types of Information Systems

• Management Information Systems
• Types of reports
• Scheduled report
• Key-indicator report
• Exception report
• Drill-down report
• Ad hoc report

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General Types of Information Systems

• Management Information Systems (MISs)
• Examples
• Sales forecasting
• Financial management and forecasting
• Manufacturing planning and scheduling
• Inventory management and planning
• Advertising and product pricing

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General Types of Information Systems

• Executive Information Systems (EISs)
• Used at executive level of the organization
• Highly aggregated form
• Data types
• Soft data news and nonanalytical data
• Hard data facts and numbers

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General Types of Information Systems

• Executive Information Systems (EISs)
• Examples
• Executive-level decision making
• Long-range and strategic planning
• Monitoring internal and external events
• Crisis management
• Staffing and labor relations

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Information Systems that Span Organizational
Boundaries
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Information Systems that Span Organizational
Boundaries

• Decision Support Systems (DSSs)
• Designed to support organizational decision
  making
• What-if analysis
• Example of a DSS tool Microsoft Excel
• Text and graphs
• Models for each of the functional areas
• Accounting, finance, personnel, etc.

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Information Systems that Span Organizational
Boundaries

• Expert Systems (ESs)
• Mimics human expertise by manipulating knowledge
• Rules (If-then)
• Inferencing

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Information Systems that Span Organizational
Boundaries

• Office Automation Systems (OASs)
• Examples
• Communicating and scheduling
• Document preparation
• Analyzing data
• Consolidating information

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Information Systems that Span Organizational
Boundaries

• Collaboration Technologies
• Virtual teams
• Videoconferencing
• Groupware
• Electronic Meeting Systems (EMSs)

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Information Systems that Span Organizational
Boundaries

• Functional Area Information Systems
• Geared toward specific areas in the company
• Human Resources
• Benefits
• Marketing

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Information Systems that Span Organizational
Boundaries

• Global Information Systems
• International IS
• Transnational IS
• Multinational IS
• Global IS

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Chapter 4Enterprise-WideInformation Systems
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Chapter Objectives

• Understand how information technology supports
  business activities
• Understand enterprise systems and how they
  evolved
• Understand software applications that are
  internally or externally focused
• Understand how to implement enterprise systems

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Enterprise Systems

• Enterprise systems
• Also known as enterprise-wide information systems
• Information systems that allow companies to
  integrate information across operations on a
  company-wide basis

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Before an entreprise system
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With an entreprise sytem
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Types of Enterprise Systems

• Packaged applications
• Custom applications
• Stand-alone applications

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Types of Enterprise Systems

• Enterprise Resource Planning
• Integrated applications
• ERP systems
• Baan
• Oracle
• PeopleSoft
• SAP

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Types of Enterprise Systems

• ERP Implementation
• Modules
• Customizations
• Best practices
• Business process reengineering (BPR)

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Types of Enterprise Systems

• Customer Relationship Management (CRM)
• Sales Force Automation (SFA)
• New opportunities for competitive advantage
• Examples
• MGM
• American Airlines
• Marriott International

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CRM system
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Types of Enterprise Systems

• Supply Chain Management (SCM)
• Supply chain the producers of supplies that a
  company uses
• Supply network
• What if supply chain does not collaborate?
• Two objectives of upstream information flow
• Accelerate product development
• Reduce costs associated with suppliers

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Supply chain management
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The Formula for Enterprise System Success

• Secure executive sponsorship
• Get help from outside experts
• Thoroughly train users
• Take a multidisciplinary approach to
  implementation

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Questions

1. List the different classes of information systems
   described in this chapter. How do they differ
   from each other?
2. Of the information systems listed in the chapter,
   how many do you have experience with? What
   systems would you like to work with? What types
   of systems do you encounter at the university you
   are attending?
3. Consider an organization that you are familiar
   with, perhaps the one in which you work or one
   with which you have done business. Describe the
   type of information systems that organization
   uses and whether or not they are useful or
   up-to-date. List specific examples for updating
   or installing information systems that improve
   productivity or efficiency.

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Chapter 5Information SystemsDevelopment
Acquisition
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Chapter Objectives

• Understand the process of IS management
• Understand the system development life cycle
  (SDLC)
• Understand alternative approaches to system
  development
• Understand in-house system development
• Understand external acquisition, outsourcing, and
  end-user development

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The Need for Structured Systems Development

• Systems analysis and design the process of
  designing, building, and maintaining information
  systems
• Systems analyst
• Blending technical and managerial expertise

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The Need for Structured Systems Development

• Evolution of IS development
• From art to a discipline
• Standardized development methods
• Software engineering

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The Need for Structured Systems Development

• Options for Obtaining Information Systems
• Build your own
• Buy a prepackaged system
• Outsource development to a 3rd party
• End user development

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The Need for Structured Systems Development

• Information Systems Development in Action
• Breaking large complex problems into manageable
  pieces
• Decomposing large, complex problems

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The Need for Structured Systems Development

• System Construction Process
• Identify a large IT problem to solve
• Break the large problem into several smaller,
  more manageable pieces
• Translate each piece (small problem) into
  computer programs
• Piece together each program into an overall
  comprehensive IS that solves the problem

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The Need for Structured Systems Development

• The Role of Users in the Systems Development
  Process
• Knowledgeable of needs
• Effective partnership

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Information Systems Analysis and Design

• Systems Analyst performs analysis and design
  based upon
• Understanding of organizations objectives,
  structure and processes
• Knowledge of how to exploit information
  technology for advantage

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Systems Analysis and Design Core Concepts

• Major goal to improve organizational systems by
  developing or acquiring software and training
  employees in its use
• Application software, or a system, supports
  organizational functions or processes

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Systems Analysis and Design Core Concepts

• System Turns data into information and includes
• Hardware and system software
• Documentation and training materials
• Job roles associated with the system
• Controls to prevent theft or fraud
• The people who use the software to perform their
  jobs

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Software Engineering Process

• A process used to create an information system
• Consists of
• Methodologies
• A sequence of step-by-step approaches that help
  develop the information system
• Techniques
• Processes that the analyst follows to ensure
  thorough, complete and comprehensive analysis and
  design
• Tools
• Computer programs that aid in applying techniques

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System

• A system is an interrelated set of business
  procedures used within one business unit working
  together for a purpose
• A system has nine characteristics
• A system exists within an environment
• A boundary separates a system from its environment

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Characteristics of a System

• Components
• Interrelated Components
• Boundary
• Purpose
• Environment
• Interfaces
• Constraints
• Input
• Output

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Important System Concepts

• Decomposition
• The process of breaking down a system into
  smaller components
• Allows the systems analyst to
• Break a system into small, manageable subsystems
• Focus on one area at a time
• Concentrate on component pertinent to one group
  of users
• Build different components at independent times

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Important System Concepts

• Modularity
• Process of dividing a system into modules of a
  relatively uniform size
• Modules simplify system design
• Coupling
• Subsystems that are dependent upon each other are
  coupled
• Cohesion
• Extent to which a subsystem performs a single
  function

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A Modern Approach to Systems Analysis and Design

• Systems Integration
• Allows hardware and software from different
  vendors to work together
• Enables procedural language systems to work with
  visual programming systems
• Visual programming environment uses client/server
  model

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Data and Processes

• Three key components of an information system
• Data
• Data Flows
• Processing Logic
• Data vs. Information
• Data
• Raw facts
• Information
• Derived from data
• Organized in a manner that humans can
• understand

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Data and Processes

• Data
• Understanding the source and use of data is key
  to good system design
• Various techniques are used to describe data and
  the relationship amongst data
• Data Flows
• Groups of data that move and flow through the
  system
• Include description of sources and destination
  for each data flow
• Processing Logic
• Describe steps that transform data and events
  that trigger the steps

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Approaches to Systems Development

• Process-Oriented Approach
• Focus is on flow, use and transformation of data
  in an information system
• Involves creating graphical representations such
  as data flow diagrams and charts
• Data are tracked from sources, through
  intermediate steps and to final destinations
• Natural structure of data is not specified
• Disadvantage data files are tied to specific
  applications

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Approaches to Systems Development (2)

• Data-Oriented Approach
• Depicts ideal organization of data, independent
  of where and how data are used
• Data model describes kinds of data and business
  relationships among the data
• Business rules depict how organization captures
  and processes the data

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Databases and Application Independence

• Database
• Shared collection of logically related data
• Organized to facilitate capture, storage and
  retrieval by multiple users
• Centrally managed
• Designed around subjects
• Customers
• Suppliers
• Application Independence
• Separation of data and definition of data from
  applications

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Role of the Systems Analyst

• Study problems and needs of an organization
• Determine best approach to improving organization
  through use of
• People
• Methods
• Information technology
• Help system users and managers define their
  requirements for new or enhanced systems

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Role of the Systems Analyst

• Assess options for system implementation
• In-house development
• Outsourced development
• Outsourced development and operation
• Commercial application
• For in-house projects, work on a team of analysts
  and developers

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Skills of a Successful Systems Analyst

• Analytical
• Understanding of organizations
• Problem-solving skills
• System thinking
• Ability to see organizations and information
  systems as systems
• Technical
• Understanding of potential and limitations of
  technology
• Managerial
• Ability to manage projects, resources, risk and
  change
• Interpersonal
• Effective written and oral communication skills

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Systems Development Life Cycle

• System Development Methodology
• Standard process followed in an organization
• Consists of
• Analysis
• Design
• Implementation
• Maintenance

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Systems Development Life Cycle

• Series of steps used to manage the phases of
  development for an information system
• Consists of four phases
• Planning and Selection
• Analysis
• Design
• Implementation and Operation

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Systems Development Life Cycle

• Phases are not necessarily sequential
• Each phase has a specific outcome and deliverable
• Individual companies use customized life cycle

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Phases of the Systems Development Life Cycle

• Systems Planning and Selection
• Two Main Activities
• Identification of need
• Investigation and determination of scope
• Systems Analysis
• Study of current procedures and information
  systems
• Determine requirements
• Generate alternative designs
• Compare alternatives
• Recommend best alternative

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Systems Development Life Cycle

• System Design
• Logical Design
• Concentrates on business aspects of the system
• Physical Design
• Technical specifications
• Implementation and Operation
• Implementation
• Hardware and software installation
• Programming
• User Training
• Documentation
• Operation
• System changed to reflect changing conditions
• System obsolescence

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Alternative approaches

• Prototyping
• Building a scaled-down working version of the
  system
• Advantages
• Users are involved in design
• Captures requirements in concrete form
• Rapid Application Development (RAD)
• Utilizes prototyping to delay producing system
  design until after user requirements are clear
• Joint Application Design (JAD)
• Users, Managers and Analysts work together for
  several days
• System requirements are reviewed
• Structured meetings

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Summary

• Information systems analysis and design
• Process of developing and maintaining an
  information system
• Modern approach to systems analysis
• Process-Oriented
• Data-Oriented

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Summary

• Systems Development Life Cycle (SDLC)
• Systems Planning and Selection
• Systems Analysis
• Systems Design
• Systems Implementation
• Alternatives to Systems Development Life Cycle
• Prototyping
• Rapid Application Development (RAD)
• Joint Application Design (JAD)

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Questions

• In what way are organizations systems?
• List and explain the different phases in the
  systems development life cycle.
• Why is it important to use systems analysis and
  design methodologies when building a system? Why
  not just build the system in whatever way seems
  to be quick and easy? What value is provided
  by using an engineering approach?
• Explain the traditional application-based
  approach to systems development. How is this
  different from the data-based approach?
• What is prototyping?
• What is JAD? What is Participatory Design?

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Chapter 6 Managing the Information Systems
Project
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Learning Objectives

• Discuss skills required to be an effective
  project manager
• Describe skills and activities of a project
  manager during project initiation, planning,
  execution and closedown
• Explain Gantt Charts and Network Diagrams
• Review commercial project management software
  packages

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Case of Pine Valley Furniture

• Manufacturing Company
• Product Wood Furniture
• Market U.S.
• Organized into functional areas
• Manufacturing
• Sales
• Three independent computer systems were converted
  to a database in 1990s

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Managing the Information Systems Project

• Focus of project management
• To ensure that information system projects meet
  customer expectations
• Delivered in a timely manner
• Meet constraints and requirements

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Managing the Information Systems Project

• Project Manager
• Systems Analyst responsible for
• Project initiation
• Planning
• Execution
• Closing down
• Requires diverse set of skills
• Management
• Leadership
• Technical
• Conflict management
• Customer relations

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Project Management Process

• Project
• Planned undertaking of related activities to
  reach an objective that has a beginning and an
  end
• Four Phases
• Initiation
• Planning
• Execution
• Closing down

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Initiating the Project

1. Establish project initiation team
2. Establish relationship with customer
3. Establish project initiation plan
4. Establish management procedures
5. Establish project management environment and
   workbook

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Planning the Project

• Describe project scope, alternatives and
  feasibility
• Scope and Feasibility
• Understand the project
• What problem is addressed
• What results are to be achieved
• Measures of success
• Completion criteria

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Planning the Project

• Divide the project into manageable tasks
• Work breakdown structure
• Gantt chart
• Estimate resources and create a resource plan
• Develop a preliminary schedule
• Utilize Gantt Charts and Network Diagrams
• Develop a communication plan
• Outline communication processes among customers,
  team members and management
• Types of reports
• Frequency of reports

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Planning the Project

• Determine project standards and procedures
• Specify how deliverables are tested and produced
• Identify and assess risk
• Identify sources of risk
• Estimate consequences of risk
• Create a preliminary budget
• Develop a statement of work
• Describe what the project will deliver
• Set a baseline project plan
• Estimate of projects tasks and resources

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Executing the Project

• Execute baseline project plan
• Acquire and assign resources
• Train new team members
• Keep project on schedule
• Monitor project progress
• Adjust resources, budget and/or activities
• Manage changes to baseline project plan
• Slipped completion dates
• Changes in personnel
• New activities
• Maintain project workbook
• Communicate project status

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Closing Down the Project

• Termination
• Types of termination
• Natural
• Requirements have been met
• Unnatural
• Project stopped
• Documentation
• Personnel Appraisal
• Conduct post-project reviews
• Determine strengths and weaknesses of
• Project deliverables
• Project management process
• Development process
• Close customer contract

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Representing and Scheduling Project Plans

• Gantt Charts
• Useful for depicting simple projects or parts of
  large projects
• Show start and completion dates for individual
  tasks
• Network Diagrams
• Show order of activities

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Summary

• Skills of an effective project manager
• Activities of project manager
• Initiation
• Planning
• Execution
• Closedown
• Gantt Charts and Network Diagrams
• Commercial PM Software

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Questions

1. List and describe the common skills and
   activities of a project manager. Which skill do
   you think is most important? Why?
2. Describe the activities performed by the project
   manager during project initiation.
3. Describe the activities performed by the project
   manager during project planning.
4. Describe the activities performed by the project
   manager during project execution.

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Chapter 7 Systems Planning
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Learning Objectives

• Discuss the content of and need for a Statement
  of Work and Baseline Project Plan
• Describe a structured walkthrough

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First documents

• Baseline Project Plan (BPP) internal document
• Scope
• Benefits
• Costs
• Risks
• Resources
• Statement of Work (SOW) Outlines objectives and
  constraints of the project to the customer
• Describes deliverables
• Outlines work needed to be performed

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Building the Baseline Project Plan

• Objectives
• Assures that customer and development group have
  a complete understanding of the proposed system
  and requirements
• Provides sponsoring organization with a clear
  idea of scope, benefits and duration of project
• Four Sections
• Introduction
• System Description
• Feasibility Assessment
• Management Issues

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Building the Baseline Project Plan

• Introduction
• Brief overview
• Recommended course of action
• Project scope defined
• Units affected
• Interaction with other systems
• Range of system capabilities

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Building the Baseline Project Plan

• System Description
• Outline of possible alternative solutions
• Narrative format
• Feasibility Assessment
• Project costs and benefits
• Technical difficulties
• High-level project schedule

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Building the Baseline Project Plan

• Management Issues
• Outlines concerns that management may have about
  the project
• Team composition
• Communication plan
• Project standards and procedures

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Reviewing the Baseline Project Plan

• Objectives
• Assure conformity to organizational standards
• All parties agree to continue with project

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Reviewing the Baseline Project Plan

• Walkthrough
• Peer group review
• Participants
• Coordinator
• Presenter
• User
• Secretary
• Standards Bearer
• Maintenance Oracle
• Activities
• Walkthrough review form
• Individuals polled
• Walkthrough action list
• Advantages
• Assures that review occurs during project

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Summary

• Baseline Project Plan (BPP)
• Created during project initiation and planning
• Contains
• Introduction
• High-Level description of system
• Outline of feasibility
• Overview of Management Issues
• Statement of Work (SOW)
• Describes what project will deliver
• Lists all work to be performed

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Questions

• What is contained in a Baseline Project Plan?
  Are the content and format of all baseline plans
  the same? Why or why not?
• Describe the structured walkthrough process.
  What roles need to be performed during a
  walkthrough?

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Chapter 8 Determining System Requirements
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Learning Objectives

• Describe options for designing and conducting
  interviews
• Discuss planning an interview
• Discuss using questionnaires to determine system
  requirements
• Explain advantages and disadvantages of observing
  workers and analyzing business documents to
  determine requirements

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Learning Objectives

• Learn about Joint Application Design (JAD) and
  Prototyping
• Discuss appropriate methods to elicit system
  requests
• Examine requirements determination for Internet
  applications

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Activities in Requirement Gathering
2.0 Use most appropriate investigation techniques
4.0 Document the requirements
1.0 Identify the right Stakeholders Artefacts
3.0 Determine duration
0.0 Outline information to be sought
Objective determine the functions information
that must be provided by the information system
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Performing Requirements Determination

• Gather information on what the system should do
  from many sources
• Users
• Reports
• Forms
• Procedures

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Performing Requirements Determination

• Characteristics for gathering requirements
• Impertinence
• Question everything
• Impartiality
• Find the best organizational solution
• Relaxation of constraints
• Attention to detail
• Reframing
• View the organization in new ways

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Deliverables and Outcomes

• Types of deliverables
• Information collected from users
• Existing documents and files
• Computer-based information
• Understanding of organizational components
• Business objective
• Information needs
• Rules of data processing
• Key events

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Deliverables and Outcomes
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Traditional Methods for Determining Requirements
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Traditional Methods for Determining Requirements

• Interviewing and Listening
• Gather facts, opinions and speculations
• Observe body language and emotions
• Guidelines
• Plan
• Checklist
• Appointment
• Be neutral
• Listen
• Seek a diverse view
• Interview Questions
• Open-Ended
• No prespecified answers
• Close-Ended
• Respondent is asked to choose from a set of
  specified responses

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Traditional Methods for Determining Requirements

• Administering Questionnaires
• More cost-effective than interviews
• Choosing respondents
• Should be representative of all users
• Types of samples
• Convenient
• Random sample
• Purposeful sample
• Stratified sample
• Design
• Mostly closed-ended questions
• Can be administered over the phone, in person or
  over the Internet or company intranet

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Traditional Methods for Determining Requirements

• Questionnaires Vs. Interviews
• Interviews cost more but yield more information
• Questionnaires are more cost-effective

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Traditional Methods for Determining Requirements

• Directly Observing Users
• Serves as a good method to supplement interviews
• Often difficult to obtain unbiased data
• People often work differently when being observed

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Analyzing Procedures and Other Documents

• Types of information to be discovered
• Problems with existing system
• Opportunity to meet new need
• Organizational direction
• Names of key individuals
• Values of organization
• Special information processing circumstances
• Rules for processing data

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Modern Methods for Determining Requirements

• Joint Application Design (JAD)
• Brings together key users, managers and systems
  analysts
• Purpose collect system requirements
  simultaneously from key people
• Conducted off-site
• Prototyping
• Repetitive process
• Rudimentary version of system is built
• Replaces or augments SDLC
• Goal to develop concrete specifications for
  ultimate system

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Joint Application Design (JAD)

• Participants
• Session Leader
• Users
• Managers
• Sponsor
• Systems Analysts
• Scribe
• IS Staff
• End Result
• Documentation detailing existing system
• Features of proposed system

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Prototyping

• Quickly converts requirements to working version
  of system
• Once the user sees requirements converted to
  system, will ask for modifications or will
  generate additional requests
• Most useful when
• User requests are not clear
• Few users are involved in the system
• Designs are complex and require concrete form
• History of communication problems between
  analysts and users
• Tools are readily available to build prototype

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Prototyping

• Drawbacks
• Tendency to avoid formal documentation
• Difficult to adapt to more general user audience
• Sharing data with other systems is often not
  considered
• Systems Development Life Cycle (SDLC) checks are
  often bypassed

159
Summary

• Interviews
• Open-ended and close-ended questions
• Preparation is key
• Questionnaires
• Must be carefully designed
• Can contain close-ended as well as open-ended
  questions

160
Summary

• Other means of gathering requirements
• Observing workers
• Analyzing business documents
• Joint Application Design (JAD)
• Prototyping

161
Questions (1)

1. Describe systems analysis and the major
   activities that occur during this phase of the
   systems development life cycle.
2. What are some useful character traits for an
   analyst involved in requirements determination?
3. Describe four traditional techniques for
   collecting information during analysis. When
   might one be better than another?
4. What are the general guidelines for conducting
   interviews?
5. What are the general guidelines for designing
   questionnaires?
6. Compare collecting information by interview and
   by questionnaire. Describe a hypothetical
   situation in which each of these methods would be
   an effective way to collect information system
   requirements.

162
Questions (2)

1. What are the general guidelines for collecting
   data through observing workers?
2. What are the general guidelines for collecting
   data through analyzing documents?
3. Describe how prototyping can be used during
   requirements determination. How is it better or
   worse than traditional methods?

163
Chapter 9 Structuring System RequirementsProces
s Modeling
164
Learning Objectives

• Understand the logical modeling of processes
  through studying data flow diagrams
• How to draw data flow diagrams using rules and
  guidelines
• How to decompose data flow diagrams into
  lower-level diagrams
• Balancing of data flow diagrams

165
Learning Objectives

• Discuss the use of data flow diagrams as analysis
  tools
• Discuss process modeling for Internet
  Applications

166
Process Modeling

• Graphically represent the processes that capture,
  manipulate, store and distribute data between a
  system and its environment and among system
  components
• Data flow diagrams (DFD)
• Graphically illustrate movement of data between
  external entities and the processes and data
  stores within a system

167
Process Modeling

• Modeling a systems process
• Utilize information gathered during requirements
  determination
• Structure of the data is also modeled in addition
  to the processes
• Deliverables and Outcomes
• Set of coherent, interrelated data flow diagrams

168
Process Modeling

• Deliverables and outcomes (continued)
• Context data flow diagram (DFD)
• Scope of system
• DFDs of current system
• Enables analysts to understand current system
• DFDs of new logical system
• Technology independent
• Show data flows, structure and functional
  requirements of new system

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Data Flow Diagramming Mechanics

• Data Flow
• Depicts data that are in motion and moving as a
  unit from one place to another in the system
• Drawn as an arrow
• Select a meaningful name to represent the data

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Data Flow Diagramming Mechanics

• Data Store
• Depicts data at rest
• May represent data in
• File folder
• Computer-based file
• Notebook
• Drawn as a rectangle with the right hand vertical
  line missing
• Label includes name of the store as well as the
  number

172
Data Flow Diagramming Mechanics

• Process
• Depicts work or action performed on data so that
  they are transformed, stored or distributed
• Drawn as a rectangle with rounded corners
• Number of process as well as name are recorded

173
Data Flow Diagramming Mechanics

• Source/Sink
• Depicts the origin and/or destination of the data
• Sometimes referred to as an external entity
• Drawn as a square symbol
• Name states what the external agent is
• Because they are external, many characteristics
  are not of interest to us

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Data Flow Diagramming Definitions

• Context Diagram
• A data flow diagram (DFD) of the scope of an
  organizational system that shows the system
  boundaries, external entities that interact with
  the system and the major information flows
  between the entities and the system
• Level-O Diagram
• A data flow diagrams (DFD) that represents a
  systems major processes, data flows and data
  stores at a higher level

177
Developing DFDs An Example

• Hoosier Burgers automated food ordering system
• Context Diagram contains no data stores

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Developing DFDs An Example

• Next step is to expand the context diagram to
  show the breakdown of processes

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Data Flow Diagramming Rules

• Basic rules that apply to all DFDs
• Inputs to a process are always different than
  outputs
• Objects always have a unique name
• In order to keep the diagram uncluttered, you can
  repeat data stores and data flows on a diagram

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Data Flow Diagramming Rules

• Process
• No process can have only outputs (a miracle)
• No process can have only inputs (black hole)
• A process has a verb phrase label

• Data Store
• Data cannot be moved from one store to another
• Data cannot move from an outside source to a data
  store
• Data cannot move directly from a data store to a
  data sink
• Data store has a noun phrase label

183
Data Flow Diagramming Rules

• Source/Sink
• Data cannot move directly from a source to a sink
• A source/sink has a noun phrase label

• Data Flow
• A data flow has only one direction of flow
  between symbols
• A fork means that exactly the same data go from a
  common location to two or more processes, data
  stores or sources/sinks

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Data Flow Diagramming Rules

• Data Flow (Continued)
• A join means that exactly the same data come from
  any two or more different processes, data stores
  or sources/sinks to a common location
• A data flow cannot go directly back to the same
  process it leaves
• A data flow to a data store means update
• A data flow from a data store means retrieve or
  use
• A data flow has a noun phrase label

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Decomposition of DFDs

• Functional decomposition
• Act of going from one single system to many
  component processes
• Repetitive procedure
• Lowest level is called a primitive DFD
• Level-N Diagrams
• A DFD that is the result of n nested
  decompositions of a series of subprocesses from a
  process on a level-0 diagram

186
Balancing DFDs

• When decomposing a DFD, you must conserve inputs
  to and outputs from a process at the next level
  of decomposition
• This is called balancing
• Example Hoosier Burgers
• In Figure 5-4, notice that there is one input to
  the system, the customer order
• Three outputs
• Customer receipt
• Food order
• Management reports

187
Balancing DFDs

• Example (Continued)
• Notice Figure 5-5. We have the same inputs and
  outputs
• No new inputs or outputs have been introduced
• We can say that the context diagram and level-0
  DFD are balanced

188
Balancing DFDsAn Unbalanced Example

• In context diagram, we have one input to the
  system, A and one output, B
• Level-0 diagram has one additional data flow, C
• These DFDs are not balanced

189
Balancing DFDs

• We can split a data flow into separate data flows
  on a lower-level diagram

190
Balancing DFDsFour Additional Advanced Rules
191
Guidelines for Drawing DFDs

• Completeness
• DFD must include all components necessary for
  system
• Each component must be fully described in the
  project dictionary or CASE repository
• Consistency
• The extent to which information contained on one
  level of a set of nested DFDs is also included on
  other levels

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Guidelines for Drawing DFDs

• Timing
• Time is not represented well on DFDs
• Best to draw DFDs as if the system has never
  started and will never stop
• Iterative Development
• Analyst should expect to redraw diagram several
  times before reaching the closest approximation
  to the system being modeled
• Primitive DFDs
• Lowest logical level of decomposition
• Decision has to be made when to stop decomposition

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Using DFDs as Analysis Tools

• Gap Analysis
• The process of discovering discrepancies between
  two or more sets of data flow diagrams or
  discrepancies within a single DFD
• Inefficiencies in a system can often be
  identified through DFDs

194
Using DFDs in Business Process Reengineering

• Example IBM Credit
• Credit approval process required six days before
  Business Process Reengineering (see Fig 5-12)

195
Using DFDs in Business Process Reengineering

• After Business Reprocess Engineering, IBM was
  able to process 100 times the number of
  transactions in the same amount of time

196
Summary

• Data flow diagrams (DFD)
• Symbols
• Rules for creating
• Decomposition
• Balancing
• DFDs for Analysis
• DFDs for Business Process Reengineering (BPR)

197
Questions

1. What is a data flow diagram? Why do systems
   analysts use data flow diagrams?
2. What is decomposition? What is balancing? How
   can you determine if DFDs are not balanced?
3. Explain the convention for naming different
   levels of data flow diagrams.
4. How can data flow diagrams be used as analysis
   tools?

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Chapter 10Structuring System RequirementsConcep
tual Data Modeling
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Learning Objectives

• Define key data-modeling terms
• Conceptual data model
• Entity-Relationship (E-R) diagram
• Entity type
• Entity instance
• Attribute
• Candidate key
• Multivalued attributes
• Relationship
• Degree
• Cardinality
• Associative entity

200
Learning Objectives

• Ask the right kinds of questions to determine
  data requirements for an IS
• Learn to draw entity-relationship diagrams (ERD)
• Review the role of conceptual data modeling in
  overall design and analysis of an information
  system
• Discuss relationships and associative entities
• Discuss relationship between data modeling and
  process modeling

201
Conceptual Data Modeling

• Representation of organizational data
• Purpose is to show rules about the meaning and
  interrelationships among data
• Entity-Relationship (E-R) diagrams are commonly
  used to show how data are organized
• Main goal of conceptual data modeling is to
  create accurate E-R diagrams
• Methods such as interviewing, questionnaires and
  JAD are used to collect information
• Consistency must be maintained between process
  flow, decision logic and data modeling
  descriptions

202
Process of Conceptual Data Modeling

• First step is to develop a data model for the
  system being replaced
• Next, a new conceptual data model is built that
  includes all the requirements of the new system
• In the design stage, the conceptual data model is
  translated into a physical design
• Project repository links all design and data
  modeling steps performed during SDLC

203
Deliverables and Outcomes

• Primary deliverable is the entity-relationship
  diagram
• There may be as many as 4 E-R diagrams produced
  and analyzed during conceptual data modeling
• Covers just data needed in the projects
  application
• E-R diagram for system being replaced
• An E-R diagram for the whole database from which
  the new applications data are extracted
• An E-R diagram for the whole database from which
  data for the application system being replaced
  are drawn

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Deliverables and Outcomes

• Second deliverable is a set of entries about data
  objects to be stored in repository or project
  dictionary
• Repository links data, process and logic models
  of an information system
• Data elements that are included in the DFD must
  appear in the data model and conversely
• Each data store in a process model must relate to
  business objects