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System Analysis and Design Documentation: Design Documentation:

Flowchart and DFDManagement Information

Systems

Daniel Haryanto, S.Kom, MM – daniel@pmbs.ac.id

Systems DocumentationSystems Documentation

Documentation explain how IS operate

include

NarrativesOther written

include InputProcess

Odesc

ribe

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Flowcharts

Narratives communication

utput

Common methods: Flowcharts and Data Flow Diagrams (DFD)

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FlowchartingFlowchartingDefinition

A graphical representation of some part of an information s stem

Flowcharts classifications• Systems flowcharts

information system

Snapshot of an IS

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y• Program flowcharts• Document flowcharts• Process flowcharts• Schematic flowcharts

Benefits of FlowchartBenefits of Flowchart

1. Promotes understanding of a process

2. Identifies problem areas and opportunities for process

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opportunities for process improvement

3. Provides a way of trainingemployees

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Flowcharting ConventionsFlowcharting Conventions

Flowcharts should be read from top to bottom and left to rightFlowcharts should have plenty of “white space”Flowcharts should have a titleFlowcharts should be organized in columns that depict areas of responsibilityDocuments involved in a business process h ld h l i i d l

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should have a clear origin and a clear terminationRough drafts of flowcharts should be discussed by people involved in the process

Flowcharting SymbolsFlowcharting SymbolsTerminal points

Data recordsInput/output

Action or

Manualinput

Flow

Document

Action or process

Manual operation

Decision

Off-linestorage

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Multidocument

On-page connector

Direct access storage device

Off-page connector

Description or comment

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Flowcharting ExampleFlowcharting Example

Annie, please document the paperwork involved in acquiring office supplies frominvolved in acquiring office supplies from

company’s Central Supplies Department !!

Annie explains the process as follows:Reordering supplies requires a requisition request. When I need more stationary, for

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request. When I need more stationary, for example , I fill out two copies of a Goods Requisition Form (GRF). I send the first

copy to central supplies and file the second copy here in the office.

Flowcharting ExampleFlowcharting ExampleAnnie’s Working Process

Requesting Department Central Supplies Department

Goods Requisition Form (GRF)

A

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A

File

Goods Requisition Form (GRF)

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Flowcharting ExampleFlowcharting ExampleUniversity Library• The process of ordering textbooks in a university library

begins with faculty deciding which textbook they want to useuse.

• They communicate relevant information about the textbook to the administration officer.

• Then the administration officer prepares a standard university book requisition form in three copies:

• For requesting FM• For the administration office• For the library

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y• The library then prepares Purchase Orders for textbook

publishers.• Each PO has three copies:

• For the publisher• For the library• For the accounting department

Continue

Flowcharting ExampleFlowcharting ExampleUniversity Library (cont’d)• When the publisher sends the books, the library staff

prepares two copies of a receiving reportp p p g p• One is filled to indicate that the goods were

received• The second is forwarded to the accounting

department• The publisher sends a billing statement (invoice)

directly to the accounting department.

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• Once all documents have been matched and verified, the accounting department writes a check or sends an electronic funds transfer to the publisher.

• The library staff then sort the books and stock the shelves.

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Flowcharting ExampleFlowcharting ExampleFACULTY ADMINISTRATION

OFFICELIBRARY ACCOUNTING PUBLISHER

StartPrepare

book

Prepare PO3 4

1

Select textbook

Send textbook

information

requisition form

Book requisition

forms

Purchase orders

N 1

2

R i

Match and verify

documents

Verified document

Prepare books and

invoice

Send invoice

3

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Textbook information

A

A

Receive books

Receiving reports

4N

A

Make payment

Send books

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Data Flow DiagrammingData Flow Diagramming

DFD primarily used in the systems development process• Example

As a tool for analyzing an existing systemAs a planning aid for creating a new system

Emphasizes specific data and what is being done to themThe diagram reveals

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The diagram reveals• The data flows into and out processes• Rules to process data• The stores of data• The external entities

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DFD SymbolsDFD SymbolsProcess• transforms data inflows into data

outflows – labeled with verbProcess

outflows labeled with verb phrases

Data Flow• refers to the data itself – labeled

with noun phrasesExternal entity• any person or organization External

Data flow

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y p goutside the boundary of an information system

Data Store• a place where data can be kept

– labeled with noun phrases

External Entity

Data Store

DFD ConventionsDFD Conventions

All processes should have unique namesThe inputs to a process should differ fromThe inputs to a process should differ from the outputs to a processAny single DFD should not have more than about seven processesNo process can have only inputs. If an object

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has only outputs, then it must be an external entityData cannot be moved directly from one data store to another data store

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DFD ConventionsDFD Conventions

Data cannot move directly from an external entity to a data store or vice versaData of any concern to the system cannot move directly from an external entity to another external entityA data flow has only one direction between symbols

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A data flow cannot go directly back to the same process it leavesA data flow can go directly into a data store and vice versa

Leveled Sets of DFDsLeveled Sets of DFDs

DFD hierarchical set of diagrams.• Each diagram in the set is a decomposition of the g p

preceding diagram.Begins with a context diagramContext Diagram• The top level of DFD• The entire information system is a process

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(process name is a system name)• The process is related to system’s external

entities and data stores• Very helpful in establishing the system’s

boundaries

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DFD ExampleDFD ExampleTimbaktu Open University’s registration processing system hasbeen in operation for over a decade. It serves the registrar, thestudents, the registration clerk, and the instructors. At the time ofregistration, students turn in a course request sheet, which isprocessed by the system to develop course schedules that are top y y pbe reviewed and approved by the registration clerk. A copy ofthe student’s approved course schedule is given to the student.The system also generates class lists for instructors and asummary enrollment report for the registrar.

The registration processing system has four specific processes:prepare course schedules, approve course schedules, prepareclass listings, and prepare reports. The system uses six datastores: course request data course status data student data

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stores: course request data, course status data, student data,course schedule data, student schedule data, and registrationdata. Process 1.0 prepare course schedules, has three sub-processes: enter and edit course data, process course requestdata, and process student schedules.

Prepare a context diagram, a level-zero DFD, and a level-oneDFD for process 1.0.

DFD Example (cont’d)DFD Example (cont’d)Context Diagram for a registration processing system

Registration

Registration processing

system

Student Registration clerkCourse request

sheets

Approved course schedules

Approved course schedules

Course schedules

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Registrar Instructor

Class listingsSummaries of class

enrollments

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DFD Example (cont’d)DFD Example (cont’d)Level-zero DFD relating to the class registration process

StudentCourse request sheets

Course request dataCourse request data

Course request data

Instructor

1.0Prepare course

schedules

3.0Prepare

class listings

sheets

Course status data

Course status data

Student data

Course schedule dataCourse schedule

data

Student schedule data

Student schedule data

Course schedulesApproved course schedules

Class listings

Student class data

Updated Student schedule data

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2.0Approve course

schedules4.0

Prepare reports

Student data

Registration clerk

Course schedules

Approved course

schedules Student

Approved course schedules

Registration data

Student class data

Registrar

Summaries of class enrollments

DFD Example (cont’d)DFD Example (cont’d)Level-one DFD for preparing course schedules for the student

registration system Student Course

request sheets

Course request data

Edited course request Edited course request data

Course schedule data

1.1Enter and

edit course data

Course status data

Edited course request data

1.2Process course

request data

Edited course request dataCourse schedule

data

Course status data

Student data

Student dataUpdated student schedule

data

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1.3Process student

schedule

Student schedule data

Student schedule data

Course schedules

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DFD-Flowcharts ComparisonsDFD-Flowcharts ComparisonsCharacteristics Data Flow Diagram Flowchart

Symbols Four Many

OrganizationLeveled sets, each depicting more detail than the last

Columns representing areas of responsibilitythe last p y

Numbers

Processes are numbered in the following formats: Level zero, 1.0; Level 1, 1.1; Level two, 1.1.1, and so on

Numbers are used for on and off-page connectors, not for processes

Focus

Focus on data and how they move between business processes,

Concerned with data, but also with documents and

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external entities, and data stores

documents and processing tools

Use of "lines"Lines represent data, they are labeled with noun phrases

Lines represent movement between processes, areas of responsibility, and the like; they are not labeled

DFD-Flowcharts ComparisonsDFD-Flowcharts ComparisonsReceive Payment

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Customer

PaymentMail

paymentPayment

docsCheck and remittance

advice

Customer Mailroom

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FlowchartData Flow Diagram

1.0Receive Payment

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