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Mata kuliah Analisis dan Desain Sistem Informasi Data · PDF fileMata kuliah Analisis dan...

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  • Mata kuliah Analisis dan Desain Sistem Informasi

    Data Flow Diagram{Diagram Arus Data}

    Arif Akbarul Huda, S.Si, M.Eng

  • 3

    DFDs describe the flow of data or information into and out of a system what does the system do to the data?

    A DFD is a graphic representation of the flow of data or information through a system

    Data Flow Diagrams (DFD)

  • Flow chart shows flow of Control . DFD shows flow of Data The flowchart describes boxes that

    describe computations, decisions, interactions & loops.

    It is important to keep in mind that data flow diagrams are not flowcharts and should not include control elements .

    DFD is not a flow chart

  • TYPES OF DFDData flow diagrams (DFDs) are categorized as either logical or physical. 1) LOGICAL DFD:- A logical DFD focuses on the business and how the business operates. It describes the business events that take place and the data required and produced by each event.

    2) PHYSICAL DFD:- A physical DFD shows how the system will be implemented.

  • DFD COMPONENTS Data Flow Diagrams are composed of the four

    basic symbols shown below:-

    Process box

    D Data Store

    ExternalEntity

    Data Flow

  • external entity - people or organisations

    that send data into the system or receive data from the system

    process - models what happens to the data i.e. transforms incoming data into outgoing data

    data store - represents permanent data that is used by the system

    data flow - models the actual flow of the data between the other elements

    4 Main Elements

  • 1)External Entity:-

    The sharp cornered rectangles(or simply boxes) in a DFD indicates entities.

    The External Entity symbol represents sources of data to the system or destinations of data from the system.

    Entities are people things, organizations etc

    EntityEntity

  • ENTITIESStudentStudent

    DoctorDoctor

    TeacherTeacherManagerManager

    CashierCashier

    UserUserCustomerCustomer

  • The rounded cornered rectangles in a DFD indicate processes The Process symbol represents an activity that transforms or manipulates the data (combines, reorders, converts, etc.).

    2) Process:-

    ProcessProcess

  • Processes

    Accounting System

    Accounting System

    Grading SystemGrading System

    Reservation System

    Reservation System

    Patient Administration

    System

    Patient Administration

    SystemMarketing System

    Marketing System

  • 3) Data Store:- Opened sided rectangles in DFD indicates data store.

    The Data Store symbol represents data that is not moving (delayed data at rest).

    A Data Store is a repository of data.

    Data can be written into the data store. This is depicted by an incoming arrow.

    Two data stores cannot be connected by a data flow.

  • Data can be read from a data store. This is depicted by an outgoing arrow.

    External entity cannot read or write to the data store.

  • Data Store

  • 4) Data Flow:-

    Arrow symbol in DFD indicate data flow The Data Flow symbol represents movement of data

  • Data

  • RULES OF DATA FLOW Data can flow from -external entity to process -process to external entity -process to store and back -process to process

    Data cannot flow from -external entity to external entity -external entity to store -store to external entity -store to store

  • This diagram represents a banking process, which maintains customer accounts.

    In this example, customers can withdraw or deposit cash, request information about their account or update their account details.

    The five different symbols used in this example represent the full set of symbols required to draw any business process diagram.

    EXAMPLE 1

  • Level 0 DFD The level 0 DFD (also known as the

    context level DFD ) is the simplest DFD. The outermost level (Level 0) is

    concerned with how the system interacts with the outside world.

    This level basically represents the input and output of the entire system.

    LEVELS OF DFD LEVELS OF DFD

  • 1. Identify your main system

    2. Identify the external people who interact with the system

    3. Decide what data these entities will enter into the system

    4. Determine what these entities expect as output from the system

    How to create Level 0 DFD

  • Context Level DFD for a Mail Order Business

    ORDER PROCESSINGORDER PROCESSINGCUSTOMERCUSTOMERORDER

    DELIVERY

  • The basic module of the system are represented in this phase and how data moves through different module is shown.

    The level 1 DFD provides a high level view of the system that identifies the major processes and data stores.

    Level 1 DFD

  • 1. Focus on your process and break it into 2 or more sub-processes

    2. Identify what data flows between these processes and between the entities

    3. Identify What permanent data files are used in this system

    4. Note that no new entities can be introduced

    How to create Level 1 DFD

  • Delivery

    Credit

    Status

    Level 1 DFD for a Mail Order Business

    CUSTOMERCUSTOMERSALES

    PROCESSINGSALES

    PROCESSING

    ACCOUNTING SYSTEM

    ACCOUNTING SYSTEM

    CUSTOMER DATABASE

    Customer no.

    Credit Status

    ORDERS

    Order

    OrderOrder

  • Each process from level 1 is exploded even more into sub processes. This decomposition continues for each level.The number of levels possible depends on the complexity of the system

    2-Level DFD and other level of DFD

  • LEVELLING DFD A context diagram is expanded into a number of inter-related processes. Each process may be further expanded into a set of inter-connected sub processes. This procedure of expanding a DFD is known as leveling.

  • 1. With a dataflow diagram, users are able to visualize how the system will operate, what the system will accomplish, and how the system will be implemented

    2. Data flow diagrams can be used to provide the end user with physical idea of how the data they input ultimately has an effect upon the structure of the whole system.

    3. The old systems dataflow diagrams can also be drawn up and compared with the new systems dataflow diagrams to draw comparisons in order to help implement a more efficient system.

    The value of a DFD

  • Order SystemOrder System

    OrderSystemCustomer Warehouse

    Order

    Invoice

    New customer

    Picking Slip

    Order

    Ship Statement

  • New customer

    Order SystemOrder System

    1

    AddCustomer

    New info D Customer

    1 Master

    Customer

    2

    ProcessCustomer

    Order

    OrderCust Info

    D Back 3 Order

    D Inventory 2 Master

    BackorderProc Info

    3Warehouse Picking

    Slip Produced

    Pending Order

    Packing slip Warehouse

    4

    Shipping Prepare

    D Customer 1 Master

    Ship N/A

    5

    CustomerBill

    Produce

    Bill N/A

    Bill Info

    Shipping B/O info

    Order

    Picked

    CustomerShip statement

    Cust Bill

  • Customer

    2.1

    VerifyCustomer

    OrderD Customer 1 Master

    Need to establish

    Customer

    2.2

    Verify Item

    OrderD Inventory 2 Master

    Notify

    Valid

    2.3

    CheckAvailable

    2.4

    UpdateCommit

    2.5

    Create Order

    D Inventory 2 Master

    D Shipping 4 Taxes

    D Back 3 Order

    Valid Item

    Order SystemOrder System

    Back Order

    Avail

    Update

    Tax

    Ord

    Pending Order

  • Questions ?

  • Your Assignment

  • http://en.wikipedia.org/wiki/Physical_Data_Flowhttp://www.visual-paradigm.com/product/bpva/tutorials/dfd.jsphttp://www.civil.utm.my/staff/file/141/file/CIMLectureNotes2011.pdfhttp://spot.colorado.edu/~kozar/DFDtechnique.htmlhttp://www.fbk.eur.nl/PRJ/MEETEYEES/dfd.htmHttp://ratandon.mysite.syr.edu/cis453/notes/DFD_over_Flowcharts.pdfhttp://www.slideshare.net/mohit4192/dfd-exampleshttp://ecourses.vtu.ac.in/nptel/courses/Webcoursecontents/IIScBANG/System%20Analysis%20and%20Design/pdf/module5.pdf

    References

    http://en.wikipedia.org/wiki/Physical_Data_Flowhttp://www.visual-paradigm.com/product/bpva/tutorials/dfd.jsphttp://www.visual-paradigm.com/product/bpva/tutorials/dfd.jsphttp://www.civil.utm.my/staff/file/141/file/CIMLectureNotes2011.pdfhttp://www.civil.utm.my/staff/file/141/file/CIMLectureNotes2011.pdfhttp://spot.colorado.edu/~kozar/DFDtechnique.htmlhttp://www.fbk.eur.nl/PRJ/MEETEYEES/dfd.htmhttp://ratandon.mysite.syr.edu/cis453/notes/DFD_over_Flowcharts.pdfhttp://ratandon.mysite.syr.edu/cis453/notes/DFD_over_Flowcharts.pdfhttp://www.slideshare.net/mohit4192/dfd-exampleshttp://ecourses.vtu.ac.in/nptel/courses/Webcoursecontents/IIScBANG/System%20Analysis%20and%20Design/pdf/module5.pdfhttp://ecourses.vtu.ac.in/nptel/courses/Webcoursecontents/IIScBANG/System%20Analysis%20and%20Design/pdf/module5.pdfhttp://ecourses.vtu.ac.in/nptel/courses/Webcoursecontents/IIScBANG/System%20Analysis%20and%20Design/pdf/module5.pdf

    Slide 1Data Flow Diagrams (DFD)Slide 3Slide 4Slide 54 Main ElementsSlide 7Slide 8Slide 9Slide 103) Data Store:-Slide 12Slide 13Slide 14Slide 15Slide 16Slide 18Slide 19Slide 20Level 1 DFDS

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