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									                                                                                                           Assignment 3
                                                                                                                                                            effective date
                                                                                                name

                                                                                       ssn                         (1,*)              (1,1)                         new salary
                                                                                                                           received             Salary
                                                                                                       Employee             salary             Change
                                                                                      address                                raise

                  InfSci 2510                                                            phone
                                                                                                                                                                      order#

    Information System Analysis and Design                                                              Sales             help    (1,*)             Sales
                                                                                                       Employee        negotiated                   Order             customer

                                    Lecture 5                                                                                                                       total sale
                                                                                                          D
                                                                                                                                        commission
                                    9/30/2002
                                                                                      Sales                                   Sales
                                                                                                                   (1,1)
                                                                                      Mentor           serves to             Trainee
                                                                                                         lead




                             Assignment 3                                                                    Assignment 3
One table for each entity set, we have…                                           Consider the relationships…

•   Employee(SSN, name, address, phone).                                          • ReceivedSalaryRaise is 1:N, we may simply extend the
                                                                                    table SalaryChange, but there are no new columns to add.
•   SalesEmployee(SSN→Employee).
•   SalaryChange(SSN→Employee, EffDate, newSalary).                               • HelpNegotiated is M:N, we need a new table.
                                                                                  • HelpNegotiated(SSN→SalesEmployee,
•   SalesOrder(OrderNo, Customer, TotalSale).
                                                                                                     OrderNo→SalesOrder,
•   SalesMentor(SSN→SalesEmployee).                                                                  commission).
•   SalesTrainee(SSN→SalesEmployee).                                              • ServesToLead is 1:N, we may extend the table
The arrow “→” indicates a column which serves as                                    SalesTrainee, adding the column for SSN of the mentor.
 a foreign key to the table referred to.                                          • SalesTrainee(SSN→SalesEmployee, SSN→SalesMentor).




                             Assignment 3                                                                 Assignment 3
                     Employee                             Sales Employee
                                                                                                                   Sales Employee
        SSN      Name        Address      Phone                SSN
                                                                                                                           SSN




                     Salary Change
               SSN    Eff Date     New Salary
                                                                                                   Sales Mentor                                     Sales Trainee
                                                                                                       SSN                                    SSN            Mentor

                                                        Help Negotiated
               Sales Order                        SSN   OrderNo      Commission
     OrderNo   Customer      Total Sale




                                                                                                                                                                                 1
                  Assignment 3
                                                                                Reading
To compute employee pay for the current month:
• Sum up all days from all salary change records           Textbook
  applicable in the current month, pro-ration of the
  monthly salary.                                          • Kendall and Kendall
• If Sales Dept Employee, sum up all the commission          Chapter 9 “Using Data Flow Diagrams”
  pay for the sales orders the employee has helped           Chapter 10 “Analyzing Systems Using Data Dictionary”
  negotiated, and the payment is already collected.
• If Sales Mentor, check the Trainees – for each with
  more than 10 successful orders (in that month), add
  the $100 bonus.
• The total is the employee’s pay for the current month.




                       Topics                                  Entity-Relationship Modeling
•    Review of Data Flow Diagram                             Analyze and Design of information structure
•    Example: World Trend’s Catalog Division                 • Primarily an analysis technique, focused on
•    The Data Dictionary                                       the information structure which supports the
•    Data Flows                                                way business is done in the application
                                                               domain. Also extends into a design technique.
•    Data Structures
                                                             • Fundamentally, we have covered the basic
•    Data Elements
                                                               steps of the database design process.
•    Data Stores
                                                               (cf. Chapter 17 – K and K)




         Database Design Process                                       Data Flow Analysis
    The basic steps:                                         Analyze and Design of processes in the business

    1. Build an Entity-Relationship Model to                 • Primarily an analysis technique, focusing on the
       understand the information structure which              business processes and the information flow between
                                                               these processes.
       supports the way business is done.
                                                             • Build a model – to understand how business is done
    2. Refine the model – reason about how we                  in the application domain. (logical DFD)
       may improve handling of the information.              • Also extends into a design tool: to reason about how
    3. Translate the ER Model into a form for                  the business processes may be re-organized.
       implementation, such as relational tables.            • Physical DFD: a tool to organize the software system
                                                               to be implemented, to automate the business.




                                                                                                                      2
 Information System Analysis & Design                                      Data Flow Diagram
2 key techniques for Information System
                                                                A graphical representation of the business
  Analysis and Design:
                                                                 processes throughout an organization,
• Entity-Relationship Model – analysis and                       consisting of primarily four symbols.
  design of information structure in a system.
                                                                •   Rounded-Rectangle: a process
• Data Flow Diagram – analysis and design
                                                                •   Arrow: a data flow
  of the information flow (actually more of the
  business processes) in a system.                              •   Square: an external entity
                                                                •   Open-Rectangle: a data store




         Steps to develop DFD                                        Creating the Context DFD
Conceptualize data flows from top down…
                                                              • It is an overview of the entire system.
1. Make a list of business activities and use the
   list to determine the various –                            • The DFD includes input, output, and all external
                                                                entities which interact with the system.
   processes, external entities, data flows, data stores.
                                                              • The system should be labeled as Process 0, and the
2. Create a Context Diagram: with external                      name of the system should be the name of the process.
   entities and data flows to and from the system             • The external entities supply data input, and/or receive
   – which is the only process, labeled as #0.                  data output from the system, as would be expressed in
   The Context DFD should not have any data                     the data flows.
   stores, nor any detailed processes.                        • There should be no data stores – all data stores are
                                                                within the system, if there are any.




                                                                     Diagram 0 – the next level
        Context DFD Example
                                                              More detailed DFDs come from exploding the processes…
               Delivery Notice and Invoice
                                                              Diagram 0 is the DFD from exploding Process 0.
    Customer   Order Negotiation                              • Inputs and outputs remain constant in all DFDs
               Customer Order                                   produced through exploding.
                                   Manufacturing              • The effect is like taking a close-up look into a process
                                     Company
               Purchase Order
                                                                when exploding it, showing the detailed processes and
    Supplier                                                    data flows and stores which make up the parent process.
                                                              • Hierarchical functional decomposition.
                Raw Materials
                                                   Products   • Labels for processes in Diagram 0 should start with
                                                                Process#1, up to (possible about 9) detailed processes.




                                                                                                                           3
Data Flow Diagram 0 – an example                                                                              Steps to develop DFD
               Customer order
  Customer
                                             0         Raw Materials Purchase                    3. Draw the next level DFD – Diagram 0. It should
                                                                                     Supplier
              Invoice & Delivery
                                            MFG
                                           factory                                                  show major business processes and possible data
                                                                                                    stores at this level.
                                                                                                 4. Explode each process in Diagram 0 to create a Child
                                    1
                                              Customer
                                               order          2         Raw Materials Purchase
                                                                                                    Diagram for each process in Diagram 0, exploding if
           Customer order
Customer                           Sales                   Planning                                 necessary.
                                                                                                 5. Check for errors and designate good names.
                                                                  MFG order         Supplier
                                                                                                 6. Use the DFD to reason about improving the business
                             Order                          Production
                     D1
                            Records
                                                     D2
                                                               Plan                                 operation by re-organizing business processes.
                                                                                                 7. To design and implement a new system: develop the
                                    4                               3
                                                 Product                                            DFD into a physical DFD.
                                Delivery          done      Manufacturing
Invoice & Delivery                                             Floor




                 Creating Child DFDs                                                                                           Topics
  • Each process in Diagram 0 may be further exploded to
    create a more detailed child data flow diagram.                                               •   Review of Data Flow Diagram
  • Child DFD has the Diagram number by the id of the                                             •   Example: World Trend’s Catalog Division
    Parent Process. Exploding Process k in Diagram 0                                              •   The Data Dictionary
    will give us Child DFD k, and so on.
                                                                                                  •   Data Flows
  • The processes in Child DFD 3 should have identifiers
    3.1, 3.2, 3.3, … and so on, so that each process in all                                       •   Data Structures
    the DFDs has a unique id, and the decimal point                                               •   Data Elements
    indicates the vertical level of depth.
                                                                                                  •   Data Stores




       World’s Trend Catalog Division                                                                 World’s Trend Catalog Division
 …a mail order supplier of high quality, fashionable clothing.                                   …a mail order supplier of high quality, fashionable clothing.
  Customers place orders by telephone, fax, mail, or on the web.                                  Customers place orders by telephone, fax, mail, or on the web.

                        List of Business Activities                                                                List of Business Activities
 1.   Add new customers to the customer master file. When customers are added
                                                                                                 5.   Orders are sent to the warehouse where they are filled.
      to the master file, they are assigned a customer number, which is used when
      placing subsequent orders.                                                                 6.   A shipping statement is attached to the filled order. Mailing labels are
 2.   Perform inquiries to let customers know the current selling price of an item                    prepared, and the order is shipped to the customer.
      and the quantity available for sale.                                                       7.   Order information is used to produce a billing statement for all customers
 3.   Process customer orders by verifying that all order information is accurate                     charging their goods to their World’s Trend account.
      and that a record exists for the customer placing the order. If a customer                 8.   Order information is used to produce an Accounts Receivable report for
      record does not exist, it is added to the master file. As orders are entered,                   the Accounting department.
      customer and item master record fields are updated.
 4.   If a customer orders more of an item than is currently available in stock,
      back-ordered item information is sent to the inventory control department.
      When back-ordered items are received from World’s Trend suppliers, they
      are shipped to the customers.




                                                                                                                                                                                   4
                                                                                                                                                                              Data Flow Diagram 0
                         Context Level DFD                                                                                    Inventory
                                                                                                                               Control
                                                                                                                                              Back-Ordered Items
                                                                                                                                                                                                        3             Order
                                                                                                                                                                         D2    Item Master                           Picking      Warehouse
                                                                                                                                                                                                    Produce            List
                                                                         Back-Ordered Items
                                                                                                        Inventory                                 Customer                                          Picking
                                                                                                         Control              Customer                                                                Slip
                                                                                                                                                   Order                 1                                                          Customer
                                                                                                                                                                                                                                    Order
                                                                                                                                                                     Add                                                            Ready
                                                                                                                               New Customer Information            Customer                             4
                                                                                                                                                                    Order
               Request for Item Information
                                                                 0                                                              2
                                                                                                                                                                                                 Prepare                                 5
                           Item Description                                                                                                                                                     Shipment
                                                                                                                           Add
    Customer          Customer Information                   Order                                       Supplier        Customer                                                               Statement                            Ship
                                                           Processing                                                                                    D1    Customer Master                                                     Customer
                            Customer Order                                                                                Record
                                                            System                                                                                                                                                                  Order
                       Shipment Statement
                                                                                                                                                               7
                           Billing Statement
                                                                                                                                                         Produce                                                                     Shipment
                                                                                                                               Account                                                                                               Statement
                                                                                                                               Receivable
                                                                                                                                                         Account
                                                                                                                               Report                   Receivable
                                                                                                                                                          Report                           6
                                                                          Order Picking List
                          Account Receivable Report                                                     Warehouse                                                                                                Billing
     Accounting                                                      Customer Order Ready                                                                                              Produce
                                                                                                                                                                                                                 Statement
                                                                                                                                                                                        Billing                                    Customer
                                                                                                                         Accounting                                                   Statement




                        Child Diagram 1 – logical DFD                                                                    D2     Item Master          Child Diagram 3 – physical DFD
                                                                                                                                          Item bin and section Location
                1.1                 D1   Customer Master                                   1.7                                                                                            Order Item
Customer                                                    Valid Customer                                Pending                           3.1                               3.2          Record
                                                                                                                                                                                                            D6    Order Item File
 Order      Validate                                                                     Create            Order
           Customer                                                                                                       Order                        Order Item
                                                    1.6                 Customer         Pending                                       Read                               Create                                       Order Item Record
            Account                                                      Order                                            Record                       Information
                                                                                          Order                                      Order Item                          Order Item
                                               Update                                                                                                                                                                  3.3
                                                                                                                                      Record                              Record
                                              Customer          Order Totals
                      Valid Customer           Record                                                                                                                                                              Sort Order
                                                                                         Order Totals                                                                                                               Item by
                                                                                                                                                                                                                    Location
                                                                               1.5                                       D1    Customer Master                 3.4
                                                          Item Weight                             D4    Shipment Table
                                                            and Price                                                         Customer                         Get                                                      Sorted Order Item Record
                             D2     Item Master                            Calculate                                                                                            Customer Number
         Valid                                                              Order                                               Record                       Customer                                        D7
                                                                                                 Shipment                                                                                                           Sorted Order Item File
         Item                                                               Totals                                                                            Record
        Number                    Available         Available                                    Cost
                                  Quantity            Item                                                                          Customer Name, Address,                                            Sorted Order Item Record
                                                                                                                                              and Telephone
                1.2                                                                                                                                                                                                                3.6
                                                                                                                                                                   3.5                          3.7
Customer                    Valid             1.3              New                                                                                                             Customer                            Order
            Validate                                                                               D2    Item Master                                                                                             Item Line     Print Order
 Order     Order Item       Item                             Available             1.4                                                                        Format             Line       Format
                                         Determine           Quantity                                                                                                                      Order Item                            Picking
                                          Quantity                                                                                                           Customer                                                              Slip
                                                                               Update                                                                          Lines                         Lines
                                         Available                              Item
                                                                                                   New
                                                                                                 Available
                                                                               Quantity          Quantity                                                                      Order Picking Slip
                      Back-Ordered Items




           Exercise: Go with the flow…                                                                                                                        Assignment 4
• See Consulting Opportunity 9.1 (p.247)…                                                                                       • Given context level DFD.
• Bonton’s – group of 26 franchise clothing stores                                                                              • Use the description on the assignment sheet, but
• Luis Asperilla - South Street store’s manager.                                                                                  also apply common sense understanding to the
• Pamela Coburn – the system analyst.                                                                                             business of a manufacturing company.
• Cash register tape – added by clerk on calculator,                                                                            • Construct Diagram 0 – identifying the processes
  separate into departments. Checked by the manager,                                                                              and data flows through these processes.
  and entered into ledger.                                                                                                      • Explode one of the processes into a Child DFD.
• Weekly report goes to head of franchise in NY, who                                                                            • Use descriptive names – for both processes and
  sends a monthly printout the end of every month.                                                                                data flows.
• Detailed information about customers not documented.




                                                                                                                                                                                                                                                   5
                            Topics
                                                                          The Data Dictionary
•    Review of Data Flow Diagram
                                                                  • Reference documentation of data about data
•    Example: World Trend’s Catalog Division
                                                                    (that is, metadata).
•    The Data Dictionary
                                                                  • Definition of terms used throughout the
•    Data Flows                                                     project, and the organization as well.
•    Data Structures                                              • Automated – with the use of CASE tools,
•    Data Elements                                                  with easy cross reference, and consistency
•    Data Stores                                                    of use maintained.




                 The Data Dictionary
                   …related to the Data Flow Diagrams                     The Data Dictionary
Data Flow Diagram                  Data Dictionary
                                                                  The Data Dictionary should consist of the
                          Data Flow
                          Description
                                              Data
                                            Structure
                                                          Data
                                                        Element
                                                                   definitions of each of the following:
                            Form
    Data Flow                xxx
                                                                    ü Data Flows
                                               xxx        xxx
                                                                    ü Data Stores
                                                                    ü Data Structures
                          Data Store          Data        Data
                          Description       Structure   Element     ü Data Elements
                            Form
    Data Store
                             xxx
                                               xxx        xxx




                 Define the Data Flow                                                      Data Flow Description
                                                                            ID:
 • ID – identification number, or an informative name,                      Name:
                                                                            Description:
   for easy cross reference.
 • Unique descriptive name – self-explanatory, on DFD.
                                                                           Source:                     Destination:
 • General description.
                                                                           Form:
 • Source: an external entity, a process, or a data store.                   File      Screen      Report       Form      Internal

 • Destination: …ditto…                                                    Data Structure or Format:        Volume / unit Time:

 • Form: file, screen, report, form, or internal.
                                                                            Comment:
 • Name of relevant data structure or format.
 • Volume per unit time (average, peak).
 • Further comments…




                                                                                                                                     6
       Describe the Data Structure                                                       Describe the Data Structure
                                                                                          Customer Order =
…in terms of the fields that make up each record:                                           Customer Number + Customer Name +
                                                                                            Address + Telephone +
• Logical Data Structure:                                                                   Catalog Number + { Available Order Items } +
                                                                                            Merchandise Total + ( Tax ) +
  data fields used in the business operations (name of the                                  Shipping and Handling + Order Total +
  items usually indicate business intentions).                                              Method of Payment +
• Physical Data Structure:                                                                  ( Credit Card Type + Credit Card Number + Expiration Date )

  additional data fields for implementation such as:                                      Customer Name =
   -   keys to locate records in a file.                                                    First Name + (Middle Initial) + Last Name

   -   codes to identify status of master records.                                        ...
   -   transaction codes for the status of the record.                                    Method of Payment =
                                                                                            [ Check | Charge | Money Order ]
   -   repeating group entries (count of how many items, or limits)
   -   password or authentication code word (web cookies)                                 Credit Card Type =
                                                                                             [ Master Card | Visa | American Express | World Trend ]




       Describe the Data Structure                                                            Define the Data Element
                                                                                  •   Element ID.
…the algebraic notation:                                                          •   Name of the element.
   1.    =     is composed of                                                     •   Aliases (synonyms)
                                                                                  •   Short description of the data element.
   2.    +     and
                                                                                  •   Element base or derived? (base element is initially keyed into the
   3.    {}    repeating elements – any number                                        system; derived element is created in a process by logic and calculations)
                                                                                  • Type of data: numeric, date, alphabetic, character…
   4.    []    either or – one of the elements                                        (may include information for format on screen. e.g.: mmddyyyy for date)

   5.    ()    optional – may or may not include                                  •   Data length (in storage, range of values)
                                                                                  •   Input/Output formats
Non-terminal names refer to other data structures;                                •   Validation criteria (range, list of values, table, key check)
Terminal names refer to data elements.                                            •   Default value
                                                                                  •   Additional comments…




                             Data Element Description
                 ID:
                 Name:
                                                                                                        The Data Stores
                 Aliases:
                 Description:
                                                                                      • All base elements.
                 Length
                                    Element Characteristics
                                                            Alphabetic
                                                                                      • Some of the derived elements.
                 Input Format                               Alphanumeric
                 Output Format                              Date                      • Data flows contain data in transit; data
                 Default Value                              Numeric
                    Continuous or          Discrete         Base or     Derived         stores contain data – for sharing, or archive.
                                      Validation Criteria
               Continuous (range)            Discrete (list of values)                • Sometimes, data stores are for buffer only.
               Upper Limit
               Lower Limit
                                             Value:
                                             Value:
                                                             Meaning:
                                                             Meaning:
                                                                                        These are less important – usually owned by
                 Comment:
                                                                                        small department or individual.




                                                                                                                                                                   7
                The Data Store Description                                                                                            Data Store Description
                                                                                                                          ID:
                                                                                                                          Name:
      • Data Store ID                                                                                                     Aliases:
                                                                                                                          Description:
      • Data Store Name – descriptive and unique
      • Aliases                                                                                                                          Data Store Characteristics
                                                                                                                          File Type:      Manual      Computerized
      • A short description for the data store                                                                            File Format:    Text File   Spread Sheet    Database Table
                                                                                                                          Record Size:
      • File type: manual or computerized                                                                                 Number of Records (max):              (average):
                                                                                                                          Rate of Growth:
      • If computerized: file format – flat file, spread sheet,                                                           Indexes:

        database table…                                                                                                   Relevant Data Structures:

      • Size: maximum or average number of records (rate
        of growth for archive)                                                                                            Comment:

      • Indexes (how to sort and search)
      • Data structures relevant to the data store




           Creating the Data Dictionary                                                                            Using the Data Dictionary
                                                                                                       • The data dictionary is not an end in itself.
      • After (or during) the development of DFDs.                                                     • Helpful in understanding an existing system, guiding interview
      • Begin with the documents available for the existing                                              strategies and questions.
        system of business.                                                                            • To maintain consistency in the DFDs:
      • Different levels of the DFDs should use data                                                      – Base elements are never created in a process: if it is in an output flow, it
                                                                                                            must be in an input flow also.
        appropriate to the level…
                                                                                                          – A derived element must be produced by some process into which it is not
                                                                         Hours
                 D4   Time Card                                          worked
                                                                                                            input.
                                                                                                          – Elements on data flows in or out at a data store must also be contained in
D1    Employee Info       Employee                                     5.3
                          Time Card                                                                         the data store.
                                                                    Calculate
                                                 Wage Information
                                                                    Monthly
                                                                                  Current Pay Amount   • To maintain consistency in the software system:
     Employee         5
     Record                                                           Pay                                 – screen design and report and form generation
                  Produce        Employee
                 Employee        Paycheck   Employee                                                      – data formats for programming interfaces
                 Paycheck
                                                                                                       • It is important to maintain the data dictionary up-to-date; it is
                                                                                                         never completed until the whole project is completed!




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