The Database Development Process

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The Database Development Process

• MH Chapter 3

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System An inter-related set of components, with
identifiable boundaries, working together for
some purpose.
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Analysis
The process of identifying problems, opportunities
, requirements, constraints, and resources.
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Design
The business of finding a way to meet the
functional requirements within the specified
constraints using the available technology.
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Where does the Database Development Process Fit?

• Information Systems Architecture
• Conceptual blueprint of plan that expresesses the
  desired future structure for information systems
  in an organization
• Provides basis for
• Planning
• Communicating
• Integrating
• Evaluating

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Characteristics of a System

• Components
• Inter-related components
• A boundary
• A purpose
• An environment
• Interfaces
• Input
• Output
• Constraints

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INFORMATION SYSTEM Technology, data and
processes that combine to provide usable
information to users.
Data
Processes
Technology
Processes
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Information Engineering Planning

• Align IT with business strategies of an
  organization
• Identify strategic planning factors
• Identify important objectives in planning
  environment
• Develop enterprise model (Business model of
  Zachman framework)
• High level E-R diagram
• Functional Decomposition diagram
• Planning matrices

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Information Engineering Analysis

• Develop detailed specifications for the
  information systems required to support an
  organization.
• Single business or functional area
• Row 3 of Zachmans framework
• Develop conceptual data model
• Develop process model

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Information Value Chain
Data
Transformation Process
Information
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Information Engineering Design

• Logical Design
• Transform the logical models to structures that
  are specific to the DBMS being used
• Physical design
• Map database structures developed in logical
  design to physical storage structures such as
  files and tables.
• Address issues such as response time, throughput,
  security, backup, and recovery

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Process vs Data Orientation
Data
Process
Data used by the system.
Focus Stability Data Organization State
of Data
What the system is to do and when it is done.
Limited a function of stability in the
business environment.
Less volatile.
Files modeled on enterprise usage.
Files designed for individual application.
Limited redundancy
Uncontrolled duplication
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Functions of an Information System
Collect Process Store Retrieve Analyze
Disseminate
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Types of Systems
Transaction processing Management information
systems Decision support systems Expert systems
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Zachman Framework
Network or
Data Processes Technology
Lists of entities important to the business
Overview of technology architecture.
Lists of functions that the business
performs. (BPM)
Ballpark (Business Scope)
Enterprise communication diagram
Functional Hierarchy Diagram
Owner (Business Model)
E-R Diagrams (Entity Level)
E-R Diagrams (Attribute Level)
Distribution Diagram
Designer (IS Model)
Dataflow Diagrams
Database Design
Configuration Design
Process Specifications
Builder (Technology Model)
Schema and Sub-schema Definition
Detailed (Technology Specification)
Configuration Definition
Program Code
Working Application
Installed Infrastructure
Functional System
Physical Tables
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Information EngineeringImplementation

• Construct and install the system
• Create database definitions
• Schema A description of the overall logical
  structure of a database expressed in a special
  data definition language
• Subschema A logical description of a users
  view of data expressed in a special data
  definition language
• Programming
• Testing

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Conceptual Data ModelProcess Data
ModelFunctional Decomposition DiagramLogical
Design
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Strategic Information System Planning

• Increased cost of information systems
• Ability to develop systems across organizational
  boundaries
• Ensure that critical success factors/problem
  areas are addressed (back to Information
  Engineering)
• Attempt to control data redundancy and
  maintentance costs
• Application backlogs necessitate identifying
  important systems early

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Issues with Strategic IS Planning

• Top management support
• Project team involving IS specialists, users, and
  managers
• Select a planning methodology such as Information
  Engineering, Business Process Re-engineering,
  etc. to guide planning and development

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Pitfalls in Strategic Planning

• Lack of top management committment
• Lack of clarity in organizational direction or
  business conditions necessitate change
• Difficult to coordinate planning among
  decentralized business functions
• Involvement of business users/mgrs to ensure
  successful system implementation
• Strategic IS plan can not be kept up-to-date with
  changing business conditions

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Zachman Framework

• Proposed by John Zachman in 1987
• Although usually depicted as a 2 dimensional
  table
• It can be thought of as three columns in three
• dimensional space.
• Recognizes that the individuals filling the roles
  at
• each level have different views of the overall
  system.
• Each view has models that are specific to that
  view.
• The description of the system for a given level
  requires
• the models for all three columns.

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• The highest level views are the most general and
• the lowest the most specific.
• When applied to the development process,
• constraints developed at the higher levels are
  applied
• to the models at the successive levels.
• The successive levels are often developed by
  different
• individuals or teams.
• The models for each column at a given level are
  often
• developed by different individuals or teams.
• The models facilitate communication between
  levels.

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• There are models that intersect columns across
• the same level. These facilitate
  communications
• between the resources responsible for Data,
• Process and Network modeling.
• Framework enforces a holistic view of the system
• and the development process.

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Overall System Design Is

• Staged - More than on phase is involved in the
  design process.
• Iterative - Constraints encountered in each phase
  may require a review or modification to previous
  stages.
• Cooperative - Because different sets of expertise
  are required for each phase and area of focus.