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Module 5:BusinessSolutionLogical
Design
126 Module5:BusinessSolutionLogicalDesign
Module Overview
Module 3: A Services-based
Approach to Solution Design
Module 4: Business Solution
Conceptual Design
Module 5:Business Solution
Logical Design
Module 6: Beginning Physical
Design
Module 1: Course Overview
Module 2: SolutionDesign Using
the MSF
Module 7: Selecting Solution
Technologies
Module 8: SolutionDesign and the
Component Object Model
Module 9: Designing Solutions with
Microsoft Technologies
Module 10: Completing the
Physical Design
Module 11: Designing the
Presentation Layer
Module 12: Introduction to
Functional Specifications
Designing Business
Solutions
Logical Design
Basics
Activity 5.2: Identifying
Business Objects and Services
Logical Design Analysis:
Attributes and Relationships
Review
Activity 5.1: Risks of
Skipping Logical Design
Logical Design
Process
Logical Design Analysis:
Services and Objects
Activity 5.3: Identifying
Attributes and Relationships
Logical Design Analysis:
Rationalization
Activity 5.4: Logical
Design Verification
Module 5: Business
Solution Logical
Design
Module5:BusinessSolutionLogicalDesign 127
!
!!
! Overview
In this module
In this module
"
Logical Design Basics
"
Activity 5.1: Risks of Skipping Logical Design
"
Logical Design Process
"
Analysis: Business Objects and Services
"
Activity 5.2: Identifying Business Objects and Services
"
Analysis: Attributes and Relationships
"
Activity 5.3: Identifying Attributes
and Relationships
"
Logical Design Rationalization
"
Activity 5.4: LogicalDesign Verification
"
Review
The second phase of the MSF Design Process is logical design. Logicaldesign
begins after conceptual design has started, when the project team agrees that
there is sufficient information to begin the logical design. A good logicaldesign
depends greatly on a good conceptual design.
Because the MSF Design Process is an evolutionary, as well as iterative,
process, logicaldesign will greatly impact your physical design and provide
feedback into the conceptual design.
In this module, you will learn about the logicaldesign phase of the MSF
Process Model. First, you will learn the basics of logicaldesign — where it fits
into the MSF Process Model, its steps, and the tasks and outputs of the logical
design phase. Then you will learn about logicaldesign in greater detail through
the use of examples and activities based on the Ferguson and Bardell case
study.
After completing this module, you will be able to:
"
Explain the need for logicaldesign in the process of designing a business
solution.
"
Describe the role of logicaldesign in the MSF Design Process.
"
Describe the steps of logical design.
"
Identify the principles of modular design.
"
Assess the impact of implementation consideration on the logical design.
"
Design the objects and services of a business solution.
"
Derive a logicaldesign for a businesssolution from a conceptual design.
Slide Objective
To provide an overview of
the module topics and
objectives.
128 Module5:BusinessSolutionLogicalDesign
!
!!
!
Logical Design Basics
In this section
In this section
"
Logical Design in the Design Process
"
Logical Design: The Search for Organization
"
Goals of Logical Design
"
Perspective of Logical Design
"
Perspective Captured in Business
Object Models
"
Clarifying Logical Design
"
Value of Logical Design
Logical design is arguably the most difficult concept of the design process to
grasp. Both conceptual and physical design can often be understood intuitively;
however, the transition between them — logicaldesign — is often confusing.
To mitigate that confusion, you will learn about the basics of logicaldesign
before learning about the process.
In this section, you will learn how logicaldesign can be considered a search for
organization. You will learn what logicaldesign is and what it is not, as well as
the value that logicaldesign brings to the overall design.
Slide Objective
To provide an overview of
this section.
Module5:BusinessSolutionLogicalDesign 129
Logical Design in the Design Process
Conceptual Design
Scenarios
Logical Design
Physical Design
Components,
User Interface, and
Physical Database
Services and Objects,
User Interface, and
Logical Database
Logical design is the second phase of the MSF Design Process Model. Logical
design involves clearly defining the solution in terms that everyone on the
project team can understand. The inputs to logicaldesign are the scenarios of
conceptual design. The output of logicaldesign is the business object model,
which serves as the basis for physical design.
Slide Objective
To position the logical
design phase in relation to
the design process.
Lead-in
As you learned in Module 2,
logical design is the second
phase in the MSF Design
Process.
130 Module5:BusinessSolutionLogicalDesign
Logical Design: The Search for Organization
"
Definition
The process of describing the solution in
terms of the organization, structure, syntax,
and interaction of its parts
"
Purpose
To apply services-based organizing
principles to lay out the structure of the
solution and define the relationships among
its parts
"
Output
A set of business objects with
corresponding services, attributes, and
relationships; a high-level user interface
design; and a logical data model
Logical Design
Services and Objects,
User Interface, and
Logical Database
Logical design defines the constituent parts of a system and provides the
organizing framework that holds all of those detailed parts together. It
illustrates how the system is put together and how the system interfaces with
the outside world (users and other systems).
Logical design can be likened to the second stage in designing a house. In the
first stage, the customer and the architect collaborated on a rough sketch and a
short list of needs and requirements, similar to the scenarios in conceptual
design. Now, in the second stage, the architect concentrates on creating the
floor plan by organizing architectural elements such as doors and windows,
roofs and patios, and rooms and their spatial relationships into a harmonious
whole.
This module deals only with the first output — a set of objects with
corresponding services, attributes, and relationships. The high-level user
interface design is covered in Module 11: Designing the Presentation Layer,
and the logical data-store design is covered in Course 1609: Designing Data
Services and Data Models.
Slide Objective
To give an overall
description of logical design.
Lead-in
Logical design is considered
“the search for organization”
because it takes the
scenarios provided by the
conceptual design and
attempts to organize the
requirements into a solution.
Note
Module5:BusinessSolutionLogicalDesign 131
Goals of LogicalDesign
"
Transform the conceptual design into a coherent view of
the entire solution
"
Describe the solution in terms of the organization,
structure, syntax, and interaction of its parts
"
Provide the basis for physical design efforts
Logical design plays a pivotal role in systems development and provides a
strong link between the technical and nontechnical team members. It provides a
structure that allows independent team members to work effectively in parallel
while coordinating with external projects and architects. The logicaldesign
describes the system and the solution in broad terms. This description includes
details about the organization, structure, syntax, and interaction of the elements
of the solution. Logicaldesign defines the system elements, their boundaries,
the services they provide, and their interactions and dependencies.
Any project team member should be able to look at the logicaldesign and
identify the important structures of the solution, the objects in the system, and
how the objects interact to solve the problem.
The team might also uncover additional user or business process requirements.
If so, the team must update and iterate through the scenarios and conceptual
design, identifying how those changes affect system behavior over the life of
the project.
Slide Objective
To describe the overall
goals of the logicaldesign
phase.
132 Module5:BusinessSolutionLogicalDesign
Perspective of LogicalDesign
Conceptual
The logical design
perspective is from the
point of view of the
project team
Logical
Physical
Business
Solution
When the project team moves from conceptual to logical design, a fundamental
shift in perspective occurs. During conceptual design, the team defines the
business problem by communicating with the user and business communities.
During logical design, team members work together to define the organization,
structure, and syntax of the resulting solution. They derive logicaldesign from
the scenarios of conceptual design, thus providing structure while preserving
the semantics of the problem captured in conceptual design.
Slide Objective
To highlight that the logical
design of the solution is
based on the project team’s
perspective of the solution.
Lead-in
While conceptual design
viewed the problem from the
perspective of the user,
logical design views the
problem from the
perspective of project team.
Module5:BusinessSolutionLogicalDesign 133
Perspective Captured in Business Object Models
"
Defines the parts of the system
"
Describes the organization of the parts
"
Describes the relationship of the parts — how they
coordinate and cooperate
"
Provides
$
Improvements in how the parts of the system operate
$
A common view of the solution among team members
$
A baseline to evaluate physical opportunities
The business object model is a major deliverable of logical design. It defines
the parts of the system, such as the object, services, and attributes.
The business object model also describes the organization of the parts within
the system and the relationships among the parts.
Overall, the business object model provides several benefits, including
improvements to how the parts of the system operate, a common view of the
solution among team members, and a baseline to evaluate physical
opportunities.
Slide Objective
To introduce the business
object model and its use
during logical design.
Lead-in
Logical design is about the
business object model. It is
used to define the parts of
the system, their
organization, and their
relationship to each other.
134 Module5:BusinessSolutionLogicalDesign
Clarifying LogicalDesign
Logical design is not
The technology solution
Optimized for a selected physical
model
But it enables you to
Specify the business needs that
technology must support
Reveal technology constraints and
opportunities
Identify appropriate technologies
that you can implement
Identify possible adjustments in the
logical design due to infrastructure
and deployment issues
Logical design should be independent of technology and physical
implementation. The primary focus is on what the system needs to do, which is
explained by an organized structure of cooperating elements. It is important that
the system be completely understood by all stakeholders before making the
commitment to technology.
In reality, certain physical constraints or opportunities should be considered in
logical design in order to validate whether the design can be implemented (or
whether it is flexible across multiple required environments). In effect, logical
design is as independent of technology as is prudent.
Decisions regarding technology are made during physical design. It is important
to distinguish between logical and physical design to separate system-behavior
issues from system-implementation issues. Implementation constraints should
be considered only after the project team verifies that the essential requirements
of the business and users have been incorporated into the logical design. This
approach does not establish a technical direction until the solution is well
understood and documented.
If physical constraints or details are discovered while the team is focusing on
logical design, that information should be taken into account during the logical
design. The logicaldesign is the base on which evaluations and decisions about
feasibility and implementation alternatives for the physical design occur.
Slide Objective
To clarify what logical
design really is and to
dismiss some possible
assumptions.
Lead-in
The following table should
help clarify what logical
design is and what it is not.
[...]... risks of not doing logicaldesign After completing this lab, you will be able to: " Articulate the value of doing logicaldesign and the risks of not doing logicaldesign Module 5:BusinessSolutionLogicalDesign 137 ! LogicalDesign Process Slide Objective To provide an overview of this section " LogicalDesign and the MSF Process Model " LogicalDesign Steps " Deliverables of LogicalDesign In this... the logicaldesign 139 140 Module5:BusinessSolutionLogicalDesign Deliverables of LogicalDesign Slide Objective To identify the outputs of logicaldesign Lead-in At the logicaldesign baseline, the project team will have a business object model " Business object model $ Services Attributes $ Each of these components of the business object model will be discussed in detail later in the module Business. .. when the logicaldesign stage takes place in the MSF Design Process Model You will also learn of the separate steps that make up the logicaldesign stage and the deliverables of those steps 138 Module5: Business SolutionLogicalDesignLogicalDesign and the MSF Process Model Slide Objective Vision Approved To show where conceptual design fits into the project life cycle Lead-in Logicaldesign begins... analysis step of the logicaldesign phase Analysis Analysis Baseline At this point in logical design, the set of objects and services has been through several iterations of discovery, but it may still need refining This will be discussed in the next module, Module 6: LogicalDesign Rationalization Module 5: Business SolutionLogicalDesignBusiness Objects Slide Objective To define a business object An.. .Module 5: Business SolutionLogicalDesign 135 Value of LogicalDesign Slide Objective To explain the benefits of a good logicaldesign and how it helps the overall success of the project Lead-in A good logicaldesign is important to the success of the project The following are some of the benefits gained by having a good logicaldesign " Creates a common view of the solution among project... Relationships The business object model includes the business objects, services, attributes, and relationships The business object model is the primary deliverable of logicaldesign Module 5: Business SolutionLogicalDesign 141 ! Analysis: Business Objects and Services Slide Objective To provide an overview of this section " Deliverables of the Analysis Baseline: Part 1 " Business Objects " Identifying Business. .. physical design or changes in the conceptual design As new elements are introduced or needed that were not included in the logical design, the design should be revisited Iteration occurs until there is consensus that the logicaldesign is sufficiently developed to be baselined The baseline is an interim milestone and serves as a reference point for change management Module 5: Business SolutionLogical Design. .. after conceptual design has begun and ends before the team reaches the Project Plan Approved Milestone Project Plan Approved Conceptual Design Baseline LogicalDesign Physical DesignLogicaldesign begins before the team baselines conceptual design and ends before the team reaches the Project Plan Approved Milestone Although logicaldesign is dependent on the products of conceptual design, logical and conceptual... DesignLogicalDesign Steps Slide Objective To introduce the three activities that make up conceptual design Lead-in LogicalDesign The logicaldesign stage is composed of two separate steps: analysis and rationalization Analysis Rationalization Although portrayed sequentially, these steps are iterative and overlapping Analysis Baseline Rationalization Baseline LogicalDesign Baseline The logical design. .. logical and conceptual (and physical) design can be carried out concurrently Logicaldesign can begin any time after the conceptual design has begun As the scenarios become available, logicaldesign can continue on an incremental basis The results of logical design, as with conceptual and physical designs, become part of the functional specification The logicaldesign may go through several iterations . Services-based
Approach to Solution Design
Module 4: Business Solution
Conceptual Design
Module 5: Business Solution
Logical Design
Module 6: Beginning Physical
Design
Module.
Module 5: Business Solution Logical
Design
126 Module 5: Business Solution Logical Design
Module Overview
Module 3: A Services-based
Approach