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CHAPTER 3 SYSTEM ANALYSIS - Coggle Diagram
CHAPTER 3 SYSTEM ANALYSIS
3.1 PRELIMINARY ANALYSIS
Fact Finding Techniques
Documentation review
Observations
Interviews
Step 4 : Prepare for the interview
Step 5 : Conduct the interview
Step 3 : Develop interview questions.
Step 6 : Document the interview.
Step 2 : Establish objectives for the interview
Step 1 : Determine the people to interview.
Step 7 : Evaluate the interview.
Questionnaires
Research
Sampling
Systematic sampling
Stratified sampling
Random sampling
System Requirements
Inputs
Processes
Outputs
Performance
Controls
Use Appropriate Fact-Finding Technique
Observations
Questionnaires
Documentation review / Sampling
Research
Interview
Analyze The Gathered Information
Step 3 : Decide how to analyze the information
Step 4 : Analyze quantitative information
Step 2 : Organize the information
Step 5 : Analyze qualitative information
Step 1 : Review the questions
Step 6 : Integrate the information
Modeling Tools and Techniques
Functional Decomposition Diagrams (FDD)
A functional decomposition diagram (FDD) is a top-down representation of a function or process.
Using an FDD, an analyst can show business functions and break them down into lower-level functions and processes
Creating an FDD is similar to drawing an organization chart
Unified Modeling Language (UML) diagrams.
Various graphical tools
Case diagrams
Sequence diagrams
Symbols that represent
Lifelines
Messages
Classes
Focuses
3.2 DATA & PROCESS MODELLING
Process Description
Modular design
iteration
selection
Symbol
sequence
Structured English
Might look familiar to programming students because it resembles pseudocode
The primary purpose of structured English is to describe the underlying business logic
Must conform to the following rules
Decision Table
Tables with three condition
Decision tree
Tables with one condition
Table with multiple outcomes
Tables with two condition
Data Flow Diagram
Data moves through an information system but does not show program logic or processing steps
A set of DFDs provides a logical model
DFD Symbols
Data flow symbol
Data store symbol
Process symbol
Entity Symbol
Creating a set of DFD
Step 1 : Draw a context diagram
Step 2: Draw a Diagram 0 DFD
Step 3: Draw the Lower-Level Diagrams
Create a graphical model of the information system based on your fact-finding results
Guidelines for drawing DFD
Data & Process Modelling Concepts
Systems analysts use many graphical techniques to describe an information system
A data flow diagram (DFD) uses various symbols to show how the system transforms input data into useful information.
Other related tools including data dictionary and process descriptions
Data Dictionary
A central storehouse of information about the system’s data
Using CASE Tools for Documentatio
An analyst uses the data dictionary to collect, document, and organize specific facts about the system
Documenting the Data Elements
Documenting the Data Flows
Documenting the Data Stores
Documenting the Processes
Documenting the Entities
Documenting the Records
Data Dictionary Reports
Documenting the Records
Logical & Physical Model
Four-Model Approach
Sequence of Models
A physical model shows how the system’s requirements are implemented
used to develop a logical model for a new information system, such tools also can be used to develop physical models of an information system