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CHAPTER 3: SYSTEM ANALYSIS - Coggle Diagram
CHAPTER 3: SYSTEM ANALYSIS
3.1 CONDUCT PRELIMINARY ANALYSIS
(NURUL AINIZAH 05DDT18F1988)
Requirements Modeling
Input
Input is something put into a system or expended in
its operation to achieve output or a result.
Within the context of systems theory, the inputs are what
are put into a system.
Typical examples are listed below:
Manufacturing employees must swipe their ID cards.....
The department head must enter overtime hours....
Students grades must be entered on machine-scannable forms....
Output
Output is the information produced by a system or
process from a specific input.
the outputs are the results obtained after running an entire process or just a small part of a process.
Typical examples are listed below.
The Web site must report online volume statistics....
The inventory system must produce a daily report...
The contact management system must generate a daily reminder list.....
Process
The processing that will take place and the hardware necessary to support that processing. It is act of taking inputted data and converting it to something usable. The system will mainly include a database to store file records.
Typical examples are listed below.
The student records systems must allow record access....
As the final step in year-end processing, the payroll system must update....
Performance
Performance or speed of the system.
The speed, capacity, and reliability of the system.
Typical examples are listed below:
The system must support 35 users....
Response time must not exceed....
Control
Protection of information resources requires a well-designed set of controls.
Computer systems are controlled
by a combination of general controls and application controls.
Typical examples are listed below.
The system must provide log-on security at the operating system level...
An employee record must be added, changed,....
The techniques used in fact-finding
Interviews
The most commonly used requirements
elicitation technique.
5 Basic Step:
Selecting Interviewees,
Designing interview questions
Preparing the interview
Conducting Interview
Postinterview follow-up
Documentation
review
Document review can help you understand how the current
system is supposed to work.
usually can obtain document samples during interviews
with the people who perform that procedure.
Observation
The observation of current operating procedures is another
fact-finding technique.
Seeing the system in action gives you additional perspective
and a better understanding of system procedures.
Questionnaires
A questionnaire is a research instrument consisting of a series of questions and other prompts for the purpose of gathering information from respondents.
Questionnaire is commonly used for system intended for use outside of the organization or for system with business users spread across many geographic location.
Sampling
A sample is a finite part of a statistical population whose properties are studied to gain information about the whole(Webster, 1985).
Sampling is the act, process, or technique of selecting a suitable sample, or a representative part of a population for the purpose of determining parameters or characteristics of the whole population.
Research
. the systematic investigation into and study of materials, sources, in order to establish facts and reach new conclusions.
Research is what we do when we have a question
or a problem we want to resolve
3.2 UNDERSTAND DATA AND PROCESS MODELLING
(NUR EMILIANA BINTI RAZDUAN ,05DDT18F1990)
Data and process modelling
-Data flow diagramming is a technique that diagrams the business processes and the data that pass among them.
-Data modeling, presents how the data created and used by processes are organized.
-Process modeling—and creating DFDs in particular—is one of the most important skills needed by systems analysts.
Data flow diagrams
-A data flow diagram(DFD) shows how data moves through an information system but does not show program logic or processing steps
Elements of Data Flow Diagrams
There are four symbols in the DFD language (processes, data flows, data stores, and external entities), each of which is represented by a different graphic symbol.
process
A process is an activity or a function that is performed for some specific business reason.
, every process must have at least one input data flow and at least one output data flow.
Data flow
Every data flow should be named with a noun.
The description of a data flow lists exactly what data elements the flow contains.
Data Store - A data store is a collection of data that is stored in some way
Every data store is named with a noun and is assigned an identification number and a description.
External Entity -Every external entity has a name and a description
-The key point to remember about an external entity is that it is external to the system, but may or may not be part of the organization.
Context Diagram
Is a top-level view of an information system that shows the system’s boundaries and scope.
To draw a context diagram, you start by placing a single process symbol in the centre of the page.
Diagram 0 DFD
Diagram 0 (the numeral zero, and not the letter O) zooms in on the system and shows major internal processes, data flows, and data stores.
Diagram 0 provides an overview of all the components that interact to form the overall system.
Lower-Level Diagrams
This set of lower-level DFDs is based on the order system. To create lower-level diagrams, you must use leveling and balancing techniques.
Leveling is the process of drawing a series of increasingly detailed diagrams, until all functional primitives are identified.
3.3Data Dictionary
(MOHD ZULFADHLI TAUFIQ)
A data dictionary, or data repository, is a central storehouse of information about the system's data.
A data dictionary, or data repository, is a central storehouse of information about the system's data.
A data dictionary, or data repository, is a central storehouse of information about the system's data.
Creating the DATA DICTIONARY
They may be created after data-flow diagram has been completed, or they may be constructed as the data-flow diagram is being developed.
The use of algebraic notation and structural records allows the analyst to develop the data dictionary and the data-flow diagram suing the top-down approach.
Data Dictionary: Data Element
Data elements are combined into records, also called data structures.
Data Dictionary: Record/ Data Structures
A record is a meaningful combination of related data elements that is included in a data flow or retained in a data store.
Example:
An auto parts store inventory record might include part number, description, supplier code, minimum and maximum stock levels, cost, and list price.
A data element, also called a data item or field, is the smallest piece of data that has meaning within an information system.
Examples: student grade, salary, ID number, account balance, company name
Data Dictionary: Data Element
Documenting the Data Elements
You must document every data element in the data dictionary
The objective is to provide clear, comprehensive information about the data and processes that make up the system.
Documenting the Data Flows
The typical attributes are as follows
Data flow name or label
Description
Alternate name(s)
Origin: The DFD beginning, or source
Destination: The DFD ending point(s)
Record
Volume and frequency: the expected number of occurrences
Data Dictionary: Data Stores
Typical characteristics of a data store are
Data store name or label
Description
Alternate name(s)
Attributes: DFD names that enter or leave the data score.
Volume and frequency: the estimated number of records, how frequently they are updated.