You can download the slides from the link given above.
In this lecture, we will focus on following points:
- How to analyze the Requirements/Structure
- Specification/Designing
- Analysis Models
- Data Models (DD)
- Functional Models (ERD)
- Behavior Models (STD)
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In this Slide:
Introduction to
Structured Analysis and Design – 5
By Abdul Razaq Ali
Lecturer, PUCIT
In Today’s Lecture
Class Test # 1
Introduction to Structured Analysis & Design
Data Modeling
Functional Modeling
Behavior Modeling
Class Test # 1 (6 min.)
Difference among RAD, Waterfall, Incremental & Spiral models.
Requirement Analysis
Requirement Analysis is a software engineering task that bridges the gap between system level requirement engineering and software design
If you don’t analyze it, its highly likely that you will build a highly elegant software that solves the wrong problem
Operational Analysis Principles
Information domain of a problem must be represented and understood.
The functions that the software is to perform must be defined.
The behavior of the software must be represented.
The models that depict information, function, and behavior must be partitioned in a manner that uncovers detail in a layered fashion.
The analysis process should move from essential information toward implementation detail.
Analysis Rules of Thumb
Model should focus on requirements that are visible within the problem or business domain.
Each element of the requirements model should add to an overall understanding of software requirements and provide insight into the information domain, function and behavior of the system.
Delay consideration of infrastructure and other nonfunctional models until design
Minimize coupling throughout the system
Be certain that requirements model provides value to all stakeholders
Keep the model as simple as it can be.
Specification
Specification Principles
Separate functionality from implementation.
Develop a model of the desired behavior of a system.
Establish the context in which software operates.
Define the environment in which the system operates
Create a cognitive model
Recognize that “the specifications must be tolerant of incompleteness and augmentable.”
Establish the content and structure of a specification amenable to change
The Software Requirements Specification
The function and performance allocated to software as part of system engineering are refined by establishing
a complete information description
a detailed functional description
a representation of system behavior
an indication of performance requirements
design constraints
appropriate validation criteria
other information pertinent to requirements.
The Software Requirements Specification (Demo)
Introduction – goals and objectives
Information description – detailed description of the problem
Functional description – description of each function
Behavioral description – operation of the software as a consequence of external events
Validation criteria – implicit review of all other requirements
Bibliography – references to all documents that relate to the software
Appendix – supplements the specifications.
Modeling
Scenario-based models
Data models
Class-oriented models
Flow-oriented models
Behavioral models
Modeling
Functional model(Flow-oriented models)
Software transforms information
To accomplish this, it must perform at least three generic functions: input, processing, and output.
When created, the software engineer focuses on problem specific functions.
Behavioral model
Most software responds to events from outside world.
This response forms the basis of the behavioral model.
Analysis Model
The Elements of the Analysis Model
Objectives
Describe what the customer requires
Establish a basis for the creation of a software design
Define a set of requirements that can be validated once the software is built.
Structure of the Analysis Model
Data Dictionary – repository that contains descriptions of all data objects consumed or produced by the software
Entity relation diagram – relationships between data objects
Data flow diagram –
Provide an indication of how data are transformed as they move through the system
Depict the functions (and sub functions) that transform the data flow
State transition diagram – how the system behaves as a consequence of external events.
Highlights of today’s lecture
How to analyze the Requirements/Structure
Specification/Designing
Analysis Models
Data Models (DD)
Functional Models (ERD)
Behavior Models (STD)
Book Reading
Roger S. Pressman “Software Engineering- A practitioner’s approach”, 7th Ed.
6.1
Questions?
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