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Required System DFM Develop Required DFDs from selected BSO

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Presentation on theme: "Required System DFM Develop Required DFDs from selected BSO"— Presentation transcript:

1 Required System DFM Develop Required DFDs from selected BSO
Specify the required solution in more detail with level 2 & 3 DFDs Support by Elementary Process Descriptions (narrative descriptions) I/O Descriptions External Entity Descriptions User Roles Resolve and document Requirement Catalogue changes Cross check processes against LDS Logical Data Store/Entity Cross Reference ensure that the necessary access paths are on the LDS

2 Required System Data Flow Diagrams
Produce full set of DFDs from chosen BSO and Logical DFDs Amend Logical DFDs to include processing identified in BSO Exclude any processing now outside the Business System Option boundary Amend Requirements Catalogue entries as appropriate eg. A requirement to accept new customers may also involve obtaining a deposit, issuing a receipt and recording the payment.

3 Level 1 DFD Example Yorkies Required System
h Driver Instructions Customer Booking Clerk b c Booking Request Drivers/Agencies Driver Admin Receipt/ Confirmation New drivers/ 1 2 agencies Driver Required i Make Find Drivers Driver Payroll Bookings Deposit d D2 Payments D3 Bookings Driver Hours and Marketing/ Agency Days Pricing D5 Drivers New Prices 4 D1 Customers 3 List of day's bookings g Payment a Record Depot Clerk Obtain Mileages, driver Customer New Prices Departures Payments hours, vehicle and Returns Invoice/Reminder Prices D4 Vehicles Vehicles into/out of Service Applications Customer & changes acceptance D3 Bookings 5 6 Location Report f e New Customers Maintain Maintain & changes relocation Vehicle Fleet Sales/Customer Customer Vehicle and Maintenance Location Info New And Sold Vehicles Records Records D1 Customers Relocation Bookings

4 Input/Output (I/O) Descriptions
Useful starting point for ongoing design screens, reports, forms etc used as basis for I/O structures From To Data flow name Data content Comments 1.3 a Booking Confirmation Customers are sent a Create Customer Booking Confirmation Confirmed Booking Customer No. Customer Name The next group of data items may be repeated if there are several bookings being confirmed at the same time Booking No. Vehicle Category Code Required Booking Start Date Required Booking Finish Date Driver Requirement (Y/N) Office No. (Start) Office Name (Start) Office No. (Finish) Office Name (Finish) { only inserted if one-way hire

5 External Entities Direct links to the computer system (on-line or off-line) on-line exteranl entities will map to User Roles May be inside or outside the organisation Documented on External Entity Descriptions ID Name Description a Customer A customer of Yorkieses who hires out or intends to hire out vehicles. b Drivers/Agencies Yorkieses employs drivers on a freelance basis for customers' bookings. If a freelance driver cannot be found a more expensive agency is contacted who will supply a driver. d Marketing/Pricing A department at Yorkieses H.Q. who can modify prices for vehicles and will receive some reports from the system. h Booking Clerk Located in the Local Offices they create bookings for customers and liaise with the customers. They also liaise with drivers and agencies, to find those available for customer bookings. g Depot Clerk Located in the depots they enter in mileage and other journey details on completion of bookings.

6 User Catalogue and User Roles
Identify how users interact on-line with the system used in Dialogue Design Closely relate to the external entities defined for the required system User Catalogue defines current jobs User Catalogue Job title Job activities description Depot Clerk Select vehicle from required category for customer on collection. Record mileage, condition, etc. on departure and return of vehicles. Driver administrator Find suitable drivers from Driver/Agency Register. Determine (Local office) availability. Find agency if no Yorkieses driver available. Record driver details on Booking Sheet.

7 User Roles User Roles from User Catalogue
One user role combines job titles where similar activities are performed in most cases user role to job title will be one-to-one Different user roles have different access privileges e.g. Driver Admin is a separate user role from Booking Clerk because only Driver Admin can enter new drivers onto the system

8 User Roles (continued)
Job title Activities Depot Clerk Depot Clerk Record vehicles departing & returning Sales/Customer Salesman Set up new customers. Records Customer records Amend customer details clerk Booking Clerk Booking clerk Take bookings from customer Driver administrator Find suitable driver for booking Driver admin Driver administrator Select new drivers and agencies from applicants

9 Define Required System Processing Summary
Specify the required system in terms of its inputs, outputs, and processing. Perform step in parallel with development of the Required System LDM Cross-check defined processing against Required System LDM Expand the chosen Business System Option into a full set of Required DFDs with supporting documentation. Amend the Requirements Catalogue to include solutions devised in this step. Develop an I/O Description to define the data content of every required system input and output Identify User Roles from User Catalogue for subsequent use in Dialogue Design.

10 Develop Required Data Model
Identify changes needed to LDM Use BSO and Requirements Catalogue Ensure all attributes have been defined for each entity Define access, archive, and security requirements for entities and attributes Check processing defined by the Data Flow Model

11 Incorporating New Requirements Yorkies Example
i. Administer one-way hires and the tracing of vehicles two relationships between Booking and Local Office: one indicating the from office and the other indicating the to office ii. Fortnightly invoicing of customers separation of Booking and Invoice so that one invoice can include several bookings in the fortnight

12 Required System LDS Yorkies Example
Vehicle Category Local required for classifier of Office /Depot Customer base of maker of employer of classified by start based at end of employed by sender of Vehicle Driver sent by drive for used for Payment requiring made by Agency from driven by split into Invoice user of to drive for for on Booking driven by paid for by part of made to Allocated Payment

13 Changes to Supporting Documentation
New Entity Descriptions New Relationship Descriptions New attributes on Entity Descriptions Update Requirements Catalogue show how requirements are met Update Logical Data Store/Entity Cross Reference Extend Entity Descriptions include non-functional requirements such as access, security and archival

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