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Research – a continuous discovery and exploration of the unknown

 systematic, objective, and comprehensive investigation of

certain phenomenon which involves accurate gathering,
recording, critical analyzing and interpreting of all facts
about the phenomenon.

Importance of Research

1. improves the quality of life

2. improves training and curriculum
3. satisfies man’s intellectual and social needs
4. reduces the burden of work
5. improves the economy of the person, community and nation

Basic Aim of Research : To solves life’s problem

In an Educational Institution

1. Institution
2. Community Extension
3. Research and Development

Characteristics of a Good Researcher

1. intellectually curios
2. prudent
3. accepts healthy criticism
4. honest
5. works well with others
6. updated

Why do we need to research today?

1. to support economic growth and development while respecting our

environment
2. to be at pace with modernization (i.e. cybernetics = highly
computerized world)
3. to provide our leaders, decision makers and ourselves with the
latest information that affect our lives
4. to develop technologies that can withstand globalization with due
consideration to our Filipino values, culture, traditions, and religious
beliefs
5. to make the Filipino more S & T – minded
Who are in the best position to do research?
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Every person who has the intellect and willingness to help solve
day-to-day problems of life: personal, family, local, national or
international in scope.

Research should NOT be viewed as an academic endeavor but a

means or tool for survival.

Research should not threaten our lives. We should control

research.

When do we formulate a research problem?

1. a gap exists in the body of knowledge

2. an unverified solution to a problem exists
3. there are contradicting findings
4. a phenomenon needs an explanation

Must for a research problem

1. objectives: S-M-A-R-T
2. 5Ms: manpower, materials methods, money, market
3. selection:
 personal interest and inclination
 scientific merit
 utility and uniqueness
 cost
 availability of qualified advisers and technologies

Review of Related Literature

To get acquainted with the existing studies related to the

research to be conducted. Who has done a similar topic before? What
has been found?

Sources:
 books
 journals
 theses and dissertations
 unpublished materials: documents
 photographs
 relics and old articles

Look for:
 arguments
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 controversies
 unclear findings
 verifiable data
 recommendations

The Research Process:

1. Problem/Objectives

- formulated based on personal observation, readings/review

of literature, problems encountered, suggestions by others

2. Theoretical/Conceptual Framework

- Theoretical Framework – based on a theory or theories to

explain why a certain phenomenon exists; abstracts
concept(s).
- Conceptual Framework – based on well-defined
concepts/constructs

3. Hypothesis

- scientific guess; done before the conduct of a study

4. Research Design

- a plan of action or scheme used in order to meet the

objectives of the study

 Types
A. Historical – occurrences and development and
experiences about the past
B. Descriptive – deals with the present status of a
situation; leads to the conduct of other studies (i.e.
experimental)
- case study, survey, content analysis,
trend analysis, feasibility study, correlation
study; done in various settings

C. Experimental – investigator manipulates and controls

one or more independent factor/variable and sees
its/their effect on the dependent variables(s) done in the
laboratory, classroom, community

5. Data Collection – uses questionnaire, interview schedule, tapes,

video, etc.
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6. Data Processing and Analysis – use of tables, figures, text

7. Data Interpretation and Discussion – meaning of the data;

relation of the present findings with others

8. Conclusions/Recommendations

System - a regularly interacting or interdependent group of elements

forming a unified whole; a collection of related parts treated as a unit
where its components interact.

System Analysis – the scientific study of the system process,

including investigation of inputs and outputs, in order to find better,
more economical, and more efficient means of processing.

System Design – the reduction of a plan or concept to a set of

specifications that describes a new or modified system.

System Analyst – are engaged in the broadly expanding field of

system analysis.

Business System – is a collection of policies, procedures, methods,

people, machine, and other elements that interacted and enable the
organizations to reach its goals.

Information System – are collections of procedures, programs,

equipment, and methods that process data and make it available to
management for decision-making.

Data – is the raw material that is processed and refined to generate

information.

Information – is the product that results from processing or

manipulating raw data.

Elements of a System

1. Subsystem – a part of a system that defined a specified

boundaries of an application.
2. Block Box – a subsystem at the lowest level whose processors
are so defined especially the input and output operation.
3. Interface – the interconnection of two or more subsystem.
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System Fundamentals

1. Environment – is the people, facilities, rules, policies and

regulations that surround a system.
2. Boundary – is the perimeter, or line of demarcation, between
the system and the environment.
3. Inputs – are those items that enter the boundaries of the system
from the environment and are manipulated by the system.
4. Processing – is the conversion of inputs, or raw materials, to
outputs, or finished results.
5. Outputs – are the product of processing.

Role of System Analyst

1. Catalyst
2. Advisor
3. Educator
4. Salesman
5. Communicator

Personal Qualities of System Analyst

1. He should be both introvert and extrovert

2. Patient with the slow
3. Perceptive with the quick
4. Must be confident as to imbue confidence
5. Must be fair and unbiased in all his/her dealings
6. Must be persistent without overbearing
7. A good listener and knows when to interject

Responsibilities of System Analyst

1. Identify the opportunity areas

2. Define the present system
3. Analyze the situation
4. Provide alternative solution
5. Design and implement the system
6. Provide maintenance
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Knowledge Required by System Analyst

1. Computer Technology and Data Processing

2. Concepts and Techniques of System Analysis and Design
Including Managerial Style Methods
3. Business Background

Data Processing Department

1. Data Processing Manager

2. System Development Manager
3. Computer Operation Manager

Common Problem of System Analyst

1. Identify the whole objectives and its boundaries

2. Dealing with problem of interface
3. Maintaining the system dynamic interaction with the
environment
4. Building flexibility of control into system
5. Resolving conflict objectives

Ideal of System Analyst

1. Knowledge
2. Education
3. Experience
4. Attributes

Job of System Analyst

1. To investigate and simulate information

2. To analyze its performances
3. To develop and evaluate ideas how to improve the system
4. To design in detail
5. To implement the new system

Aim of System Analyst

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1. To produce a new system which operate effectively

2. Efficiently
3. Economically

Skill Required by System Analyst

1. The ability to recognize, define, describe and analyze a problem

situation
2. To develop a number of alternative approaches
3. To be carried out in real life under pressure of time, money,
politics and personality
4. Communication Skills
5. Must be well organized

Recruitment of System Analyst

1. Those employed in a related work area such as work study or

programming
2. Those in user department which already affected with
computerization
3. Graduate from degree of Computer Studies

Types of System

1. Open System – also called probabilistic system, are those in

which the output , or results cannot be determined precisely, but
can only be guessed.
2. Closed System – the result or output can be predicted with
certainty

Advantages of System Analysis

1. Greater Efficiency
2. Maximizing profits
3. Resources used to the best advantage
4. Reduction of human effort
5. Faster turnaround
6. Reducing or eliminating errors in data and information
7. Consistent operations and procedures
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Limitation of System Analysis

1. Some business problems are beyond the scope of system

techniques
2. System analysis efforts cost, time and money
3. The human element can cause complications
4. Effort is required to sell a system

Duties of System Analyst

1. Project Management
2. Forecasting Simulation
3. Sales and Marketing of good and services
4. Planning the orderly flow of information throughout an entire
business enterprise
5. Modifying or redesigning existing business system
6. System implementation
7. Computer programming and Utilization
8. Database Design
9. Forms design and management
10. Establishing system policies and procedures
11. Employment and training of organization personnel
12. Work measurement
13. Work simplification
14. Office layout
15. Selection and specification of office and information
processing equipment and supplies
16. Planning and designing internal and external
communication

FEASIBILITY means that the project:

 Helps the organization attain overall objectives

 Is possible to accomplish with present organizational
resources in the following three areas:

TECHNICAL FESIBILITY

 Add on to the present system

 Technology available to meet user needs
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ECONOMIC FEASIBILTIY

 System Analyst time

 Cost of System Study
 Cost of Employees time for study
 Estimated cost of hardware
 Cost of packaged Software/Software Development Cost

OPERATIONAL FEASIBILITY

 Whether the system will operate when installed

 Whether the system will be used

Objective of Feasibility Study

1. Technical, Economic and Operational

2. Acceptable by the user
3. Flexible
4. System effectivity, efficiency

Problem of Feasibility Study

1. Time
2. Change
3. Staff

System Life Cycle

1. They are designed
2. Introduced
3. Decay
4. Evolve
5. Replaced

System Development Activities

1. Feasibility
2. Investigation
3. Design
4. Implementation

Investigation and Specification Required

1. The flow of Data

2. The form and file used
3. The procedure
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4. The equipment

Issues of Feasibility Study

1. Problem Definition
2. Turning the alternative strategies into an outline computer based
system
3. Evaluating the outline computer based system

Aspects of Feasibility Study

1. Technical Aspect
2. Operational Aspect
3. Economic Aspect

Feasibility Report

1. Description of the area of responsibility

2. Description and specification of the new system
3. Description of alternative proposed system
4. Evaluation of alternative and recommendation

Important things, which needs to be taken into accounts

1. What is the level of knowledge of computerization among the

staff
2. How good are the mechanism of consultation and discussion
3. What is the organization attitude
4. What will be the likely effect of the change on people job

The system can be develop in a variety of ways

1. Can be assigned and program with in the organization

2. Can be conducted to a consultancy firm
3. Can be develop in cooperation with other organization
4. Can be produced by modification of a bought software package

Investigation

1. Scope
2. Objective
3. Constraint
4. Resources of the investigation
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Investigation Method

1. Interview Method
2. Questionnaires
3. Observation
4. Searching through records

Questionnaire
1. Should be very carefully designed
2. Should be explicitly defined and explained
3. Should be carefully chosen
4. Should be phrased very precisely
5. Should always have space for the recipient to answer
6. Time period should always carefully designed
7. Timing
8. Follow-up

Planning the interview

1. Who is to be interviewed
2. Sequence of interview
3. The location of interview

System Analyst Link Communication

1. Auditors
2. External Bodies
3. Access User Manager
4. Top Manager
5. Clerk
6. Shop floor Operative

PROJECT PLANNING

PROJECT SCHEDULE

Describes the software development cycle for a particular project. It

enumerates the phases or stages of the project, breaks each into
discrete tasks or activities to be done, portrays the interactions among
these pieces of work and estimates the time that each task or activity
will take.

Customers Questions

1. Do you understand my problem and my needs?

2. Can you design a system that will solve my problem or satisfy
my needs?
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3. How long will it take you to develop such system?

4. How much will it cost to have you develop such a system?

Deliverables

Are those items that include anything the customer wants

demonstrated or delivered as part of the contract:

 Documents
 Demonstrations of functions
 Demonstrations of subsystem
 Demonstration of accuracy
 Demonstration of reliability, security, or speed

Activities and Milestones

Milestone - is the completion of a deliverable, which is a

measurable level of progress, since the milestone is complete when we
can turn over or demonstrate the deliverable to the customer.

Activity – is a part of the project that takes place over a period

of time and a milestone is the completion of an activity.

Phases of the Schedule

Phase is composed of steps, and each step can be sub-divided

further if necessary.

Project Role

The development schedule, sometimes called the system

development life cycle, is a broad outline for what is to be done.

1. Requirement Analysis
2. System Design
3. Program Design
4. Program Implementation
5. Testing
6. Training
7. Maintenance
8. Quality Assurance
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Personnel Characteristics

1. Ability to perform the work

2. Interest in the work
3. Experience with similar applications, tools or
techniques
4. Training
5. Ability to communicate with others
6. Ability to share responsibility with others
7. Management skills

Project Team Organization

Enhance quality, allowing development to progress

unencumbered by bureaucracy and permitting you and your customer
to track the actual cost and schedule.

1. The background and work styles of the people

working on the project.
2. The number of people working on the project.
3. The management styles of the customer and the
developer.

Structure of the Chief Programmer Team

* Chief Programmer
* Assistant Chief Programmer
* Senior Programmer
* Junior Programmer
* Librarian
* Administration
* Test Team

Cost of Building a System

Types of Cost

1. Facilities
2. People
3. Project method and Tools

Project Plan

Components of Project Plan

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1. Project Scope
2. Project Schedule
3. Project Team Organization
4. Technical Description of the Proposed System
5. Project standards, procedures and proposed methodologies
6. Quality assurance plan
7. Special development tools and techniques
8. Configuration management plan
9. Documentation plan
10. Data management plan
11. Resource management plan
12. Test plan
13. Training plan
14. Security plan
15. Maintenance plan

REQUIREMENTS ANALYSIS

A requirement is a feature of the system or a description of

something the system is capable of doing in order to fulfill the system
purpose.

System Development Activities

Requirement
What is the problem?
Analysis

What is the solution?

System
Design
What are the mechanism that
best Program
Design implement the solution?

How is the solution

constructed? Program
Implementation
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Is the problem solved?

Testing

Can the customer use the

solution? Delivery

Are enhancement needed?

Maintenance

Two Sets of Requirements

1. Requirements definition document – written in terms that

the customer can understand, the requirements definition is a
complete listing of everything the customer expects the
proposed system to do.

2. Requirement specification document – restates the

requirements definition in technical terms appropriate for the
development of a system design.
REQUIREMENTS

CONFIGURATION MANAGEMENT

DEFINITION SPECIFICATION

What is the customer can Technical description

expect the system to do of system characteristics

Customer System

Designer

Configuration Management – is a set of procedure that track

 the requirements that define the system

 the design modules that are generated from the
requirements
 the program code that implements the design
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 the tests that verify the functionality of the system

 the documents that describe the system

Functional and Nonfunctional

1. Functional Requirements – describes an interaction between

the system and its environment?

2. Nonfunctional Requirements – describes a restriction on the

system that limits our choices for constructing a solution to the
problem.

Types of Requirements

The requirements definition describes everything about how the

system is to interact with its environment. Included are the following
kinds of items.

Physical Environment:
 Where is the equipment to function?
 Is there one location or several?
 Are there any environmental restrictions, such as
temperature, humidity, or magnetic interference?

Interfaces:

 Is the input coming from one or more other systems?

 Is the output going to one or more other systems?
 Is there a prescribed way in which the data must be
formatted?
 Is there a prescribed medium that the data must use?

Users and Human Factors:

 Who will use the system?

 Will there be several types of users?
 What is the skill level of each type of user?
 What kind of training will be required for each type of user?
 How easy will it be for a user to understand and use the
system?
 How difficult will it be for a user to misuse the system?

Functionality:
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 What will the system do?

 When will the system do it?
 How and when can the system be changed or enhanced?
 Are there constraints on execution speed, response time,
or throughput?

Documentation:

 How much documentation is required?

 To what audience is the documentation addressed?
Data:

 For both input and output, what should the format of the
data be?
 How often will it be received or sent?
 How accurate must it be?
 To what degree of precision must the calculation be made?
 How much data flows through the system?
 Must any data be retained for any period of time?

Resources:

 What materials, personnel, or other resources are required

to build use, and maintain the system?
 What skills must the developers have?
 How much physical space will be taken up by the system?
 What are the requirements for power, heating, or air
conditioning?
 Is there a prescribed timetable for development?
 Is there a limit on the amount of money to be spent on
development or on hardware and software?

Security:

 Must access to the system or to information be controlled?

 How will one user’s data be isolated from others?
 How will user programs be isolated from other programs
and from the operating system?
 How often will the system be backed up?
 Must the backup copies be stored at a different location?
 Should precautions be taken against fire or theft?

Quality Assurance:
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 What are the requirements for reliability?

 How much the characteristics of the system be
demonstrated to others?
 Must the system detect and isolate faults?
 What is the prescribed mean time between failures?
 Is there a maximum time allowed for restarting the system
after a failure?
 How can the system incorporate changes to the design?
 Will maintenance merely correct errors, or will it also
include improving the system?
 What efficiency measures will apply to resource usage and
response time?
 How easy should it be to move the system from one
location to another or from one type of computer to
another?

CHARACTERISTICS OF REQUIREMENTS

Requirements describe not only the flow of information to and

from a system and the transformation of data by the system but
also the constraints on the system performance.

Requirements Serves Three Purposes

1. Allow developers to explain their understanding of how the

customer wants the system to work.
2. Tell designers what functionality and characteristic the resultant is
to have.
3. The requirements tell the test team what to demonstrate to
convince the customer that the system being delivered is indeed
what was ordered.

Requirements Validation

1. Are the requirements correct?

2. Are the requirements consistent?
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3. Are the requirements complete?

4. Are the requirements realistic?
5. Does each requirement describe something that is needed by
the customer?
6. Are the requirements verifiable?
7. Are the requirements traceable?

SYSTEM DESIGN

Is the transformation of the problem into a solution; the

resulting product is a description of the solution.

Two Parts of System Design

“How” “What”

System System Customers

Builders Designers

TECHNICAL CONCEP
DESIGN TUAL
DESIGN

Form Function
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Conceptual System Design – it produce a system specification that

tell the customer exactly what the system will do.

Characteristic of a Good Conceptual Design

1. Is written in the customer’s language

2. Contains no technical jargon
3. Describes the functions of the system
4. Is independent of implementation
5. Derives from requirements document
6. Has cross-reference to requirements
7. Incorporate all requirements in adequate detail

Technical Design – explains the system to those hardware and

software experts who will implement it. The design
describes the hardware configuration, the software
needs, the communication interfaces, the input and
output of the system, the network architecture,
and anything else that translates the requirements
into a solution to the customer’s problem.

Conceptual Design vs. Technical Design

Conceptual Technical
Design Design

“The user will be able to

route messages to any
other user on any other
network computer.”

Network topology
Protocol used
prescribed baud rate
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Technical Description

1. The system architecture: a description of the major hardware

components and their functions.
2. The system software structure: the hierarchy and functions
of the software components.
3. The data: the data structures and the data flow.

Approaches to System Design

1. All information entering the system is completely defined.

2. All required functions are specified.
3. All data produced by the system are in the format expected by
the users or other systems with which this one communicates.

PROGRAM DESIGN

Is the definition of modules and intermodular interfaces so that each

module of the system design corresponds to a new set of modules
containing program specifications.

Program Specifications – are instructions to a programmer

that describes the input, output and processing to be performed by the
module. The specifications are technical and detailed.
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Descriptions of Program Design Modules

1. Detailed Algorithms
2. Data Representations and Structures
3. Relationships among the functions performed and the data used

Design Guidelines

It allows some flexibility in creating and documenting the

resulting design modules.

1. Top-Down Approach

Examines all modules but first translates higher levels to

more concrete program specifications before descending to lower
levels.

2. Bottom-up Approach

Beginning with the lowest levels of the design rather than

the highest.

3. Modularity and Independence

Modularity is a key factor in good program design, just as it

is in system design. The working of the system was broken into
modules so that distinct functions or objects could be isolated
from one another.

4. Examination of Algorithms

 Determine whether the algorithm is always correct.

This step may sound strange, but some algorithms

work for data satisfying a certain condition but do not work
otherwise.
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 Consider the efficiency of the algorithm by investigating

the system resources it requires.

 Determine whether the algorithm is appropriate for the

particular hardware and software specified in the system
design.

5. Correctness of Algorithm

6. Efficiency of Algorithms

To consider the amount of time or memory required by the

algorithm.

7. Interpretation of the Algorithm

8. Examination of Data Types

Communication – is the transmission of a message through a

medium such as the spoken or written word from a sender to a
receiver.

External Communication – take place between an organization or

system and those beyond its boundaries.

Internal Communication – are letters, memos and other

correspondence that originate and terminate within the same
organization.

 Horizontal Communication – include the transfer of data

and information between individual at the same level on
the organization chart.

 Vertical Communication – is the transfer of information

between individuals on different levels of the organization
chart.

Job Description – the specific duties and responsibilities of system

analyst. These descriptions usually state the general responsibilities
and overall functions of the analyst. Such duties may include working
with others, assisting in the development of policies and procedures,
designing and developing new systems and so on.
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SKILLS, KNOWLEDGE AND TRAINING

Successful systems analyst exhibits certain common skills and

traits sometimes known as critical success factors. These factors
include:

 Creativity and Innovation

 Good verbal skills
 Good written communications
 A positive attitude towards others
 Technical knowledge of computers and information
systems hardware and software
 Knowledge of basic business theories and concepts
 Willingness to work with others
 Ability to solve problems

Domains of skills to work with system successfully

1. Knowledge of Business – analyst behave according to

common practices, practices, procedures and principles.
2. Technical Skills – analyst should possess a high degree of
technical and information processing skills.
3. Management and Interpersonal skills – analyst must have a
good communication skills and be able to articulate concepts
clearly.

FORMAL ORGANIZATION STRUCTURE

Organization – are composed of individuals who perform specific

roles coordinated to enable the company to achieve goals.

3 Types of Formal Organization

1. Line Organization – shows the lines of authority and chain of

command in a form organized in the classical line pattern.
2. Line & Staff Organization – this type of structure includes the
usual manager and subordinate positions representing the formal
chain of command with supplemental staff positions.

LINE POSITIONS – are indicated by solid lines.

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STAFF POSITIONS – are indicated by dotted lines.

3. Committee Organization – a position or responsibility is

organized to a group of individuals rather than to a single person.
The group shares the responsibilities delegated to that position
and makes decision by concerns.

Organization of Information Department – system analyst handle

the data processing activities for an organization.

- is engaged in a variety of activities working with

programmers, terminal operators, documentation specialist
and others on the chart.

SYSTEM DEVELOPMENT LIFE CYCLE

Cause and Effect Relationship – it is been recognized by scientist, if

it exist, the cause will always generate effect. This certainty allows
social scientist, business managers, system analyst and other s to
bring order and structure out of chaos. Cause and effect is the
foundation of system work.

Scientific Method – Philosopher John Dewey outlined the steps of a

logical approach for developing sound solutions to problem.

- is a procedure for solving problems that systematically

deals with causes and effects, evaluating the results. It is
useful for solving problem with the least expenditure of
time and effort.

Major Characteristics of Scientific Method

1. Reproducibility of results
2. Accuracy of results
3. Efficient expenditures of time and effort
4. Plan of action
5. Transferability of results

Key Aspects of the Scientific Method

1. Precise statement of the problem

2. Careful attention to detail
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3. Objective in making observation

4. Precision in analyzing data and reporting results
5. Use of mathematics and statistical techniques
6. Systematic, logical plan for problem solving
7. Evaluation of results
8. Readjustments of system to bring it more in line with objectives

SCIENTIFIC PROBLEM SOLVING PROCESS

Recognize
Problem &
Identify Causes

Express Problem in
Quantitative Terms

Analyze Choices and

Select Plans

Implement
the
Solution

Evaluate Results
and
Optimize
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STRUCTURED SYSTEM ANALSYSIS

- developed by Larry Constantine, Edward Yourdon, Chris

Gane, Thris Sarson and others.
- Enable analyst to visualize the system graphically as an
interrelated group of elements, rather than merely a
sequence of steps.

5 Phases in System Development Life Cycle

1. Planning Phase – analyst recognizes, diagnose and define

problem.
2. Analysis Phase - analyst reviews data and information on the
in-place system.
3. Design Phase – analyst identifies and considers alternative-in
this phase input and output records are prepared, forms layout,
and file specification written.
4. Development Phase – the new system is actually built. Analyst
concentrates on identifying vendors and suppliers who will be
able to provide the necessary equipment or facilities at a
reasonable price.
5. Implementation Phase – deals with the changeover to a new
or improved system.

BEGI
N

Planning Phase

Analysis Phase
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Design Phase

Development Phase

Implement-ation
Phase

END

THE TOOLS OF THE ANALYST

System Model – is a representation of an in-place or proposed system

that describes the data flow throughout the structure.

Design Diagram – is a graphic or visual representation of a

structure that includes data
flow diagrams, structures charts, decision
trees and other items.

Advantages of Design Diagrams

1. Serve as a communication tool

2. Serve as a planning tool
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3. Provide an overview of the system

4. Define roles
5. Demonstrate relationship
6. Promote logical procedures
7. Facilitate troubleshooting
8. Document a system

GANTT CHART

- developed in year 1914 by an efficiency experts Henry L.

Gantt and introduces as scheduling chart that later became
known as GANTT CHART.
- shows what activities to be performed, when each begins
and when each finished.

DECISION TREE

- is a tool that is particularly well suited for illustrating such

system depicting or showing decisions to be made, read
from left to right.

FLOWCHART

- is a graphic representation of the steps in the solution of a

problem, in which symbols represents operations, data
flow, hardware and the system plan.

2 Types of Flowchart

1. System Flowchart – illustrate the movement of data in

an organization, showing the sequence of steps through
which information moves, including related personnel,
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workstations, forms, records, processing and associated

activities.

2. Program Flowchart – show the sequence of steps

performed in a computer program.

DATA DICTIONARY

- is a composite collection of specifications about the nature

of data and information.

Data Hierarchy

1. Data Element – is the smallest unit of data that will be

processed or become part of a record.
2. Data Record – is a collection of element such as names,
addressed, or sequence of records, treated as a unit.
3. Data Stores – describes files that hold data.
4. Data Model Entities – define what records and elements
will be treated as a unit.
5. Data Flow – specify pathways for moving information.

DATA FLOW DIAGRAMS

- is a graphic illustration that shows the flow of data and

logic within a system.

DFD Symbols

4. External Entity – is a square box that specifies either the

source or the destination of the data.

Source –is a point outside the system that generates

data.
Sink – is a point outside the system that receives
data. Both are external entities, drawn as square
box.
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5. Process Symbol – is drawn as a rectangle with rounded

corners. It represents the transformation or processing of
information within a system.

6. Data Store – is a point in a system where information is

permanently or temporarily stored or held. It is shown as a
rectangle with one end open.

7. Flow Line – traces the flow of information throughout the

system.

How to Draw DFD

1. Do not mix levels of detail on one chart. Instead draw several

data flow diagrams, each with a different level of detail.

2. Select either the Gane and Sarson or Yourdon notation and used
them consistently.

3. Use a template to draw uniformly sized and shaped symbols for

permanent system documentation. Symbols may be drawn
freehand for rough or temporary diagrams.

4. Connect symbols with flow lines. Draw connections using pipes

or lines with arrowheads to show the flow of data between
symbols. Place arrowheads at each end of the pipe to show a
two-way flow of data. Place an arrowhead at one end of the pipe
to show a one way of data.

5. Name and label all symbols and connectors. Select names that
are descriptive and reflect what is being done. Place text within
each symbol describing the function or transformation takes
place. Place textual labels next to flow lines or pipes to describe
the movements or transformation of data taking place.

6. Correlate symbols to other data flow diagrams, using reference

numbers to show relationship.
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7. Desk checks all data flow diagrams to make sure each symbols is
logically connected to another and that all symbols properly
describe the flow within the system.

8. Label the top of each data flow diagram with the system name,
date prepared, name of preparer, and other pertinent
information. This will be helpful when you or others refer to the
diagram later.