Moving to Design

1
Chapter 9

• Moving to Design
• Part 1

2
Learning Objectives

• Explain the major components and levels of design
• Describe each design phase activity
• Describe common deployment environments and
  matching application architectures

3
Overview

• This chapter
• Completes the transition from analysis to design
• Discusses issues related to design of new system
• Describes all design phase activities
• Describes network and architecture design
• Analysis focuses on what system should do
  business requirements
• Design is oriented toward how system will be
  built defining structural components

4
Understanding the Elements of Design

• Design is process of describing, organizing, and
  structuring system components at architectural
  design level and detailed design level
• Focused on preparing for construction
• Like developing blueprints
• Three questions
• What components require systems design?
• What are inputs to and outputs of design process?
• How is systems design done?

5
Information Systems Architecture

• Information Systems Architecture is the process
  of making the key choices that are essential to
  the development of an information system.
  Architecture includes
• Guiding Principles
• Approaches/philosophies
• Logical representations of a system
• Hardware/Operating System
• Computing model client/server vs traditional vs
  Web-based
• Tools and technologies
• It is key, when making these choices that they
  are
• Requirements driven
• Take into consideration operational, technical
  and financial feasibility
• Made within an architectural framework

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Architecture Drivers

• There are a lot of Drivers of Architecture

Architecture
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Architecture to Design to Implementation
Looking at the Work of Developing a System as a
set of Choices, Architecture can be Described as
Highest Level Choices
Business Strategy Line of Code / Process
Step Employee / Computer
Removal of Choices
Architecture
Design
Implementation
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How is Architecture Different from Design?

• Its not Architecture can be considered
  high-level design
• Architecture includes those aspects of the design
  that are essential to the information system
• Architecture Example
• Users must be able to self-serve (guiding
  principle)
• We will use a hub and spoke design where data
  will be placed in a central data warehouse, then
  be propagated to one or more data marts.
  (approach)
• We will normalize data in the central warehouse
  and use a dimensional design in the data marts
  (approach)
• We will use Oracle 8i as our DBMS (technical
  architecture)

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Architecture vs. Detail Design

• Not Architecture
• The Order subject area will be composed of the
  following tables order_fact, customer_dim,
  product_dim and time_dim
• The customer_dim table will have the following
  attributes.

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Components Requiring Systems Design
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Analysis Objectives to Design Objectives
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Moving from Analysis to Design

• Design
• Converts functional models from analysis into
  models that represent the solution
• Focused on technical issues
• Requires less user involvement than analysis
• Design may use structured or OO approaches
• Database can be relational, OO, or hybrid
• User interface issues

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Traditional Structured and Object-Oriented
Models(Figure 9-3)
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SDLC Phases with Design Phase Activities