Data Flow Diagrams :Data Flow Diagrams


Slide 2:ELEMENTS 2. 3. 4.


Slide 3:Do’s and Don’ts when constructing a Data Flow Diagram


Zero Level DFD :Zero Level DFD FINANCE FILE STORE TOP MGMT. Financial requirements FINANCE DEPARTMENT FINANCIAL DECISIONS Updated data


First level DFD :First level DFD FINANCE DEPARTMENT 1.0 FUNDs ACQUISITION 2.0 FUNDs UTILISATION Report SOURCES OF FUNDS APPLICATION OF FUNDS Updated data Updated data Financial requirements Acquired funds TOP MANAGEMENT


Second level DFD :Second level DFD 1.0 Verify signed invoice 1.3 Verify Merchandise ordered 1.5 price invoice 1.2 Verify Acceptance merchandise 1.4 Receive Purchase authorization 1.6 Price invoice RECEIVED INVOICE APPROVED INVOICE INVOICE LOG Invoice Unsigned invoice PAYABLE INVOICE Invoice package Signed invoice Invoice details Signed invoice Invoice package Pricing detail Acceptance detail Illegal invoice Unverified invoice Audited invoice PURCHASE ORDER Purchase order details Payment voucher


DATA DICTIONARY :DATA DICTIONARY A data dictionary is a catalog of the elements in a system.these elements center around data and the way they are structured to meet the requirements and organization needs. Data dictionaries are an integral component of structured analysis since DFDs by themselves donot describes the subject of the investigation.


Slide 8:Why is a data dictionary important: 1.To manage the details in large systems. 2.To communicate a common meaning for all system elements. 3. To document the features of the system. 4.to facilitates analysis of the details in order to evaluate characteristics and determine where system changes should be made. 5.To locate errors and omissions in the system.


Slide 9:Data Dictionary For DATA STORE DATA STORE NAME : INCOMING DATA : FLOW OUTGOING DATA: FLOW Received invoice table Details about the received bills Signed invoice from 1.1 Invoice details to1.3 DESCRIPTION : DATA DICTIONARY For DATA STORE


Slide 10:Data Dictionary For DATA-ELEMENT DATA ELEMENT : DATA DESC. : TYPE : LENGTH : ALIASES : RANGE : DATA STORE : Purchase order number Identification and authorization for each order given to an outside supplier Char 7 PON 00001 to 9999999 PURCHASE ORDER TABLE, DATA DICTIONARY For DATA-ELEMENT


Slide 11:Data Dictionary For DATA-STRUCTURE DATA STRUCTURE : DESCRIPTION : CONTENTS : VOLUME : : Payment voucher Invoice and internal approvals and audits of invoiceand purchasing authorization,indicates paymentcan be made for services Invoice package,invoice details,vendor name,invoice date,amount due 200 daily DATA DICTIONARY For DATA-STRUCTURE


Slide 12:Data Dictionary For DATA-FLOW DATA FLOW NAME : DESCRIPTION : SOURCE PROCESS : DEST. PROCESS : DATA STRUCTURES : Invoice package Singed billing details from vendor and internal purchasing authorization-unaudited for correct total and tax 1.3 verify merchandise ordered 1.4 receive purchasing authorization. 1.5 price invoice Invoice package,invoice details,receiving acknowledgment,purchasing authorization DATA DICTIONARY For DATA-FLOW


Slide 13:Data Dictionary For PROCESS PROCESS NAME : INCOMING DATA : FLOW OUTGOING DATA : FLOW 1.3 Verify merchandise ordered Matches every incoming invoice with a valid purchase order number Invoice details,purchase order details Invoice package,unverified package DATA DICTIONARY For PROCESS LOGIC SUMMARY : DESCRIPTIONS