Module 5: Business Solution Logical Design 126 Module 5: Business Solution Logical Design 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: Solution Design Using the MSF Module 7: Selecting Solution Technologies Module 8: Solution Design 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 Module 5: Business Solution Logical Design 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: Logical Design Verification " Review The second phase of the MSF Design Process is logical design. Logical design begins after conceptual design has started, when the project team agrees that there is sufficient information to begin the logical design. A good logical design depends greatly on a good conceptual design. Because the MSF Design Process is an evolutionary, as well as iterative, process, logical design will greatly impact your physical design and provide feedback into the conceptual design. In this module, you will learn about the logical design phase of the MSF Process Model. First, you will learn the basics of logical design — 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 logical design 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 logical design in the process of designing a business solution. " Describe the role of logical design 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 logical design for a business solution from a conceptual design. Slide Objective To provide an overview of the module topics and objectives. 128 Module 5: Business Solution Logical Design ! !! ! 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 — logical design — is often confusing. To mitigate that confusion, you will learn about the basics of logical design before learning about the process. In this section, you will learn how logical design can be considered a search for organization. You will learn what logical design is and what it is not, as well as the value that logical design brings to the overall design. Slide Objective To provide an overview of this section. Module 5: Business Solution Logical Design 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 logical design are the scenarios of conceptual design. The output of logical design 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 Module 5: Business Solution Logical Design 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 Module 5: Business Solution Logical Design 131 Goals of Logical Design " 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 logical design 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. Logical design 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 logical design 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 logical design phase. 132 Module 5: Business Solution Logical Design Perspective of Logical Design 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 logical design 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. Module 5: Business Solution Logical Design 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 Module 5: Business Solution Logical Design Clarifying Logical Design 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 logical design 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 logical design After completing this lab, you will be able to: " Articulate the value of doing logical design and the risks of not doing logical design Module 5: Business Solution Logical Design 137 ! Logical Design Process Slide Objective To provide an overview of this section " Logical Design and the MSF Process Model " Logical Design Steps " Deliverables of Logical Design In this... the logical design 139 140 Module 5: Business Solution Logical Design Deliverables of Logical Design Slide Objective To identify the outputs of logical design Lead-in At the logical design 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 logical design stage takes place in the MSF Design Process Model You will also learn of the separate steps that make up the logical design stage and the deliverables of those steps 138 Module 5: Business Solution Logical Design Logical Design and the MSF Process Model Slide Objective Vision Approved To show where conceptual design fits into the project life cycle Lead-in Logical design begins... analysis step of the logical design 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: Logical Design Rationalization Module 5: Business Solution Logical Design Business Objects Slide Objective To define a business object An.. .Module 5: Business Solution Logical Design 135 Value of Logical Design Slide Objective To explain the benefits of a good logical design and how it helps the overall success of the project Lead-in A good logical design is important to the success of the project The following are some of the benefits gained by having a good logical design " 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 logical design Module 5: Business Solution Logical Design 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 logical design is sufficiently developed to be baselined The baseline is an interim milestone and serves as a reference point for change management Module 5: Business Solution Logical Design. .. after conceptual design has begun and ends before the team reaches the Project Plan Approved Milestone Project Plan Approved Conceptual Design Baseline Logical Design Physical Design Logical design begins before the team baselines conceptual design and ends before the team reaches the Project Plan Approved Milestone Although logical design is dependent on the products of conceptual design, logical and conceptual... Design Logical Design Steps Slide Objective To introduce the three activities that make up conceptual design Lead-in Logical Design The logical design 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 Logical Design Baseline The logical design. .. logical and conceptual (and physical) design can be carried out concurrently Logical design can begin any time after the conceptual design has begun As the scenarios become available, logical design can continue on an incremental basis The results of logical design, as with conceptual and physical designs, become part of the functional specification The logical design 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