TMF1014 - System Analysis & Design PDF

TMF1014 - System Analysis & Design How to Construct a Data Flow Diagram? Mrs. Rosita Mohamed Othman, Dr. Dayang Hanani Abg Ibrahim, Dr. Fatihah Ramli, Ms. Jennifer Fiona Wilfred Busu, Dr. Nadianatra Musa, Dr. Suhaila Saee Faculty of Computer Sciences and Information Techn...

TMF1014 - System Analysis & Design How to Construct a Data Flow Diagram? Mrs. Rosita Mohamed Othman, Dr. Dayang Hanani Abg Ibrahim, Dr. Fatihah Ramli, Ms. Jennifer Fiona Wilfred Busu, Dr. Nadianatra Musa, Dr. Suhaila Saee Faculty of Computer Sciences and Information Technology Universiti Sarawak Malaysia Semester 1, 2018-2019 A Guideline on DFD for You 1 5W + 1H 2 Introduction to DFD 3 DFD Journey 4 Tutorial Exercises 5 Test Me 6 Remind Me 7 Point Me The 5W + 1H TMF1014 - System Analysis & Design 5W + 1H Do YOU have these question marks in your mind? TMF1014 - System Analysis & Design Semester 1, 2018-2019 4 / 72 TMF1014 - System Analysis & Design 5W + 1H WHEN? WHEN to do DFD? Have you developed requirements? In previous chapter, you have learned how to gather requirements by interviewing, constructing questionnaires, observations, and many more. At that stage you need to discover and document: TMF1014 - System Analysis & Design Semester 1, 2018-2019 5 / 72 TMF1014 - System Analysis & Design 5W + 1H WHY? WHY DFD? Once documented, you need to show the data flows of information through a system. The flows show how input data is transformed to output results through a sequence of transformations (processes). These are put together into a diagram called Data Flow Diagram (DFD). DFD can help system analysts/designers and others during analysis stage to visualise and understand the current system and to represent a required system. TMF1014 - System Analysis & Design Semester 1, 2018-2019 6 / 72 TMF1014 - System Analysis & Design 5W + 1H WHO and WHERE? WHO use DFD and WHERE to use DFD? Systems analysts/designers draw DFD. DFD is used as communication aid between systems analysts and users. DFD is used during a meeting discussion and documentation. TMF1014 - System Analysis & Design Semester 1, 2018-2019 7 / 72 TMF1014 - System Analysis & Design 5W + 1H WHAT? WHAT is in DFD? DFDs are easy to learn with their few-and-simple-to-understand symbols. TMF1014 - System Analysis & Design Semester 1, 2018-2019 8 / 72  Introduction to Data Flow Diagram (DFD) TMF1014 - System Analysis & Design Introduction to DFD DFD Elements TMF1014 - System Analysis & Design Semester 1, 2018-2019 10 / 72 TMF1014 - System Analysis & Design Introduction to DFD Rules Rules of Thumb 1 Source and Sink Source/ external entities: give input to be transformed/ processed (origin) Sink/ external entities: receive information after have been transformed/ processed (destination) 2 Input and Output Input: data flow - from source to process Output: data flow - from process to sink 3 Processes A process represents actions that are performed for some specific business reason All the processes may not happen at one time E.g., might be process 1.0 happen at first. Then, if needed, process 7.0 will be performed which is based on the requirement from the business activities. TMF1014 - System Analysis & Design Semester 1, 2018-2019 11 / 72 TMF1014 - System Analysis & Design Introduction to DFD Rules Rules of Thumb (cont’d) 4 Data Store to store (update/ delete) files TMF1014 - System Analysis & Design Semester 1, 2018-2019 12 / 72 TMF1014 - System Analysis & Design Introduction to DFD Rules Rules of Thumb (cont’d) to retrieve/read information only 5 The syntax (Naming) used for designing Data Flows is simple: NOUNS or VERBS An External Entity has a NOUN phrase label Student, Finance Department, Member A Data Flow has a NOUN phrase label Student details, Payment Receipt, Student Record TMF1014 - System Analysis & Design Semester 1, 2018-2019 13 / 72 TMF1014 - System Analysis & Design Introduction to DFD Rules Rules of Thumb (cont’d) A Process has a VERB phrase label (combination of verb-adjective-noun) Create Student Record, Get Payment, Generate Report A Data Store has a NOUN phrase label Student Information, Product, Loan TMF1014 - System Analysis & Design Semester 1, 2018-2019 14 / 72 TMF1014 - System Analysis & Design Introduction to DFD Rules Rules of Thumb (cont’d) TMF1014 - System Analysis & Design Semester 1, 2018-2019 15 / 72 TMF1014 - System Analysis & Design Introduction to DFD Rules Rules of Thumb (cont’d) Data Flow that connects TMF1014 - System Analysis & Design Semester 1, 2018-2019 16 / 72 The DFD Journey TMF1014 - System Analysis & Design DFD Journey A Journey to Produce a DFD TMF1014 - System Analysis & Design Semester 1, 2018-2019 18 / 72 TMF1014 - System Analysis & Design DFD Journey Step 1: Business Activities What is Business Activities? List down business activities. Determine various External Entities (EE), Data Flows (DF), Processes (P) and Data Stores (DS). Alert with any kind of verbs and nouns. TMF1014 - System Analysis & Design Semester 1, 2018-2019 19 / 72 TMF1014 - System Analysis & Design DFD Journey Step 1: Business Activities How to Extract Business Activities? 1 Alert with any kind of verbs and nouns e.g., When regular customers call Scrumptious Recipe Cafe on the phone, they are asked for their phone number. When the number is typed into a computer, the name, address, and last order date is automatically brought up on the screen. 2 Identify the required information as follows: Event, Source, Trigger, Activity, Response, Sink e.g.: TMF1014 - System Analysis & Design Semester 1, 2018-2019 20 / 72 TMF1014 - System Analysis & Design DFD Journey Step 1: Business Activities How to Extract Business Activities? (cont’d) 3 For each business activity: identify the possible DF input(s) and DF output(s) for each input (DF),where does the data come from. Does the data (DF) come from a source (EE) or a process (P) or a file (DS)? for each output (DF), where does the data (DF) go to? Does the data is sent to another process (P) or a sink /destination (EE) or stored to a file (DS) ? 4 List the business activities as follows: process, input and output e.g., Process: Display customer record. Input: The customer number and the customer record. Output: Customer information. TMF1014 - System Analysis & Design Semester 1, 2018-2019 21 / 72 TMF1014 - System Analysis & Design DFD Journey Step 1: Business Activities Examples 1 Take customer order. Input is the order information (including the customer number). Output is the total amount due for the order. Process: Take customer order. Input: The order information (including the customer number). Output: Total amount due for the order. 2 Send order to cook. Input is the customer order. Output is the cook’s order. Process: Send order to cook. Input: The customer order. Output: The cook’s order. TMF1014 - System Analysis & Design Semester 1, 2018-2019 22 / 72 TMF1014 - System Analysis & Design DFD Journey Step 2: Context Diagram What is a Context Diagram? Context Diagram contains ONE process representing the entire system, and shows EE and DF to and from the system. DO NOT show any detailed processes (P) or data stores (DS). Ask the questions below to yourself: 1 What are you going to develop/ build? 2 Who will be interacted in the system? TMF1014 - System Analysis & Design Semester 1, 2018-2019 23 / 72 TMF1014 - System Analysis & Design DFD Journey Step 2: Context Diagram Steps Step 1 name the system (process) Step 2 identify the entities (source/ sink) Step 3 identify a name & direction of the data flow (input/ output) TMF1014 - System Analysis & Design Semester 1, 2018-2019 24 / 72 TMF1014 - System Analysis & Design DFD Journey Step 2: Context Diagram Layout Layouts often place process in the center (representing entire system) DF inputs from the left DF outputs to the right external entities which interact with the system TMF1014 - System Analysis & Design Semester 1, 2018-2019 25 / 72 TMF1014 - System Analysis & Design DFD Journey Step 2: Context Diagram Example TMF1014 - System Analysis & Design Semester 1, 2018-2019 26 / 72 TMF1014 - System Analysis & Design DFD Journey Step 3: Level-0 What is a Level-0? Level-0 Diagram is the next level. Show processes (P), but keep them general. Show data stores (DS) at this level: the content of the CD to see what is happening inside the process flow TMF1014 - System Analysis & Design Semester 1, 2018-2019 27 / 72 TMF1014 - System Analysis & Design DFD Journey Step 3: Level-0 What is a Level-0? (cont’d) Ask the questions below to yourself: What are the possible processes involved in the system? Who will be involved in the process? What is a possible DF (input/output) to execute the processes? Which data store should be for storing/ retrieving the data? TMF1014 - System Analysis & Design Semester 1, 2018-2019 28 / 72 TMF1014 - System Analysis & Design DFD Journey Step 3: Level-0 Steps Step 1 List out the processes involved when getting into the system. what are you going to do first with the system? E.g. login. what are the next thing that you are going to do? E.g. select menu Step 2 Identify the external people who interact with the process Step 3 Identify a name & direction of the data flow Step 4 Identify a name & direction of the data store to store/ retrieve the data TMF1014 - System Analysis & Design Semester 1, 2018-2019 29 / 72 TMF1014 - System Analysis & Design DFD Journey Step 3: Level-0 Layout 1 Generally move from top to bottom, left to right 2 Minimize crossed lines 3 Iterate as needed The DFD is often drawn many times before it is finished, even with very experienced systems analysts TMF1014 - System Analysis & Design Semester 1, 2018-2019 30 / 72 TMF1014 - System Analysis & Design DFD Journey Step 3: Level-0 Example TMF1014 - System Analysis & Design Semester 1, 2018-2019 31 / 72 TMF1014 - System Analysis & Design DFD Journey Step 4: Level-1 What is a Level-1? To describe in details processes inside it TMF1014 - System Analysis & Design Semester 1, 2018-2019 32 / 72 TMF1014 - System Analysis & Design DFD Journey Step 4: Level-1 Steps Step 1 Focus on the process and break it into two or more sub-processes Step 2 Identify a name & direction of the data flow Step 3 Identify a name & direction of the data store to store/ retrieve the data NOTES: 1 External Entities are NOT shown on Level-1 2 NO new entities can be introduced TMF1014 - System Analysis & Design Semester 1, 2018-2019 33 / 72 TMF1014 - System Analysis & Design DFD Journey Step 4: Level-1 Layout Sources for inputs and outputs listed at higher level Depth of DFD depends on overall system complexity Two processes generally do not need lower level More than seven processes become overly complex and difficult to read TMF1014 - System Analysis & Design Semester 1, 2018-2019 34 / 72 TMF1014 - System Analysis & Design DFD Journey Step 4: Level-1 Example TMF1014 - System Analysis & Design Semester 1, 2018-2019 35 / 72 TMF1014 - System Analysis & Design DFD Journey Step 5: Validation What is a Validation? Validation is a process to check the constructed DFDs are error free and balanced. TMF1014 - System Analysis & Design Semester 1, 2018-2019 36 / 72 TMF1014 - System Analysis & Design DFD Journey Step 5: Validation How to Validate? Syntax errors Assure correctness of DFD structure (layout) TMF1014 - System Analysis & Design Semester 1, 2018-2019 37 / 72 TMF1014 - System Analysis & Design DFD Journey Step 5: Validation How to Validate? (cont’d) Semantics errors Assure accuracy of DFD relative to actual/desired business processes TMF1014 - System Analysis & Design Semester 1, 2018-2019 38 / 72 TMF1014 - System Analysis & Design DFD Journey Step 5: Validation How to Validate? (cont’d) Examine lowest level DFDs TMF1014 - System Analysis & Design Semester 1, 2018-2019 39 / 72 TMF1014 - System Analysis & Design DFD Journey Step 5: Validation How to Validate? (cont’d) TMF1014 - System Analysis & Design Semester 1, 2018-2019 40 / 72 TMF1014 - System Analysis & Design DFD Journey Step 5: Validation How to Validate? (cont’d) Examine names carefully Naming used for designing Data Flows: NOUNS or VERBS An External Entity has a NOUN phrase label: Student, Finance Department, Member A Data Flow has a NOUN phrase label: Student details, Payment Receipt, Student Record A Process has a VERB phrase label (combination of verb-adjective-noun): Create Student Record, Get Payment, Generate Report A Data Store has a NOUN phrase label: Student Information, Product, Loan TMF1014 - System Analysis & Design Semester 1, 2018-2019 41 / 72 Tutorial Exercises TMF1014 - System Analysis & Design Tutorial Exercises Exercise 1 Question: Identify the processes, data flows, data stores, and entity in the following situation. At the end of the day a management report is produced that draws the daily goods sold amounts from the goods sold file and the daily inventory depletion amounts from the inventory file. The report is forwarded to the restaurant management. At the end of the week a weekly summary report of goods sold and inventory depletion is created and distributed on-line to the corporate headquarters in Richmond. TMF1014 - System Analysis & Design Semester 1, 2018-2019 43 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 1 While reading the description given, identify processes, data flows, data stores and external entities by using different colour of highlighters: TMF1014 - System Analysis & Design Semester 1, 2018-2019 44 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 1 Alert with any kind of VERBS and NOUNS TMF1014 - System Analysis & Design Semester 1, 2018-2019 45 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 1 Solution to Exercise 1 1 Processes: Produce Report Create Weekly Report 2 Data Flows: Management Report Daily Goods Sold Amounts Daily Inventory Depletion Amounts Weekly Summary Report 3 Data Stores: Goods Sold File Inventory File 4 External Entities: Restaurant Management Corporate Headquarters TMF1014 - System Analysis & Design Semester 1, 2018-2019 46 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 2 Question: Create a Context Diagram for the given situation. Blacktown City Library serves the information and education needs of the Blacktown community. To become a library member, applicant will need to correctly fill out an application form. Books are borrowed by members, who are required to give a membership number. Then, the system will print book issue log to the members. Members are required to return the borrowed book before it becomes overdue. When the books are returned late, the members have to made overdue payment. Besides that, the library receives new books from Purchase department. The Purchase department will furnish details of the books to the library. TMF1014 - System Analysis & Design Semester 1, 2018-2019 47 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 2 Understanding a given situation TMF1014 - System Analysis & Design Semester 1, 2018-2019 48 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 2 Business Activities TMF1014 - System Analysis & Design Semester 1, 2018-2019 49 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 2 Creating a Context Diagram TMF1014 - System Analysis & Design Semester 1, 2018-2019 50 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 2 Solution: Context Diagram TMF1014 - System Analysis & Design Semester 1, 2018-2019 51 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 3 ABC Bank provides home loans to its banking customer. Initially, a potential loan applicant meets with ABC loan officer, requests a loan for a certain amount and time frame and completes a loan application. Next, the loan officer determines the customerâĂŹs credit standing with any credit validation company, the type of loan required and available interest rates. After the loan approval, the management of ABC Bank will sell the requested loan to the loan purchasing company. Finally, the loan applicant will make monthly loan payment to the bank. Question: Using the information above, create a context diagram and Level-0 (Diagram 0) TMF1014 - System Analysis & Design Semester 1, 2018-2019 52 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 3 Understanding a given situation TMF1014 - System Analysis & Design Semester 1, 2018-2019 53 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 3 Solution: A Context Diagram Create a Context Diagram contains ONE process representing the entire system, and shows External Entities (Source/Destination) and Data Flows to and from the system. DO NOT show any detailed processes or data stores. The entire system is about Loan System. You may name it as Loan System or ABC Bank Loan System. TMF1014 - System Analysis & Design Semester 1, 2018-2019 54 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 3 Solution: A Context Diagram (cont’d) TMF1014 - System Analysis & Design Semester 1, 2018-2019 55 / 72 TMF1014 - System Analysis & Design Tutorial Exercises Exercise 3 Solution: A Context Diagram (cont’d) Create a Level-0 Diagram, the next level. Show processes , but keep them general. Show data stores at this level. TMF1014 - System Analysis & Design Semester 1, 2018-2019 56 / 72 Before you finish drawing your DFDâĂę Check for errors and make sure the labels OR naming you assigned to each element are correct and meaningful Test Me... TMF1014 - System Analysis & Design Test Me Think Pizza? Think Pasta? Choose Scrumptious Pasta Cafe... Scrumptious Pasta Cafe wants to install a system to record orders for pizzas and pastas. When regular customers call Scrumptious Recipe Cafe on the phone, they are asked for their phone number. When the number is typed into a computer, the name, address, and last order date is automatically brought up on the screen. Once the order is taken, the total, including tax and delivery, is calculated. Then the order is given to the cook. A receipt is printed. Occasionally, special offers (coupons) are printed so the customer can get a discount. Drivers who make deliveries give customers a copy of the receipt and a coupon (if any). Weekly totals are kept for comparison with last year’s performance. TMF1014 - System Analysis & Design Semester 1, 2018-2019 59 / 72 TMF1014 - System Analysis & Design Test Me Questions: Q1 Write a summary of business activities for taking an order at Scrumptious Pasta Cafe Q2 Draw a context-level data flow diagram for Scrumptious Pasta Cafe Q3 Explode the context-level diagram in (b) showing all the major processes. Call this Level-0 (Diagram 0). It should be a logical data flow diagram TMF1014 - System Analysis & Design Semester 1, 2018-2019 60 / 72 TMF1014 - System Analysis & Design Test Me Solution to Q1 A summary of the business activities for Scrumptious Pasta Cafe is: 1 Display customer record. Input is the customer number and the customer record. Output is customer information. 2 Take customer order. Input is the order information (including the customer number). Output is the total amount due for the order. 3 Send order to cook. Input is the customer order. Output is the cook’s order. 4 Print customer receipt. Input is the customer order and the customer master record. Output is the customer receipt. 5 Deliver customer order. Input is the customer receipt and coupons. Output is the delivered receipt to the customer. TMF1014 - System Analysis & Design Semester 1, 2018-2019 61 / 72 TMF1014 - System Analysis & Design Test Me Solution to Q1 (cont’d) 6 Print weekly totals. Input is the customer order and the previous year’s customer order summary. Output is the weekly performance figures. TMF1014 - System Analysis & Design Semester 1, 2018-2019 62 / 72 TMF1014 - System Analysis & Design Test Me Solution to Q2 TMF1014 - System Analysis & Design Semester 1, 2018-2019 63 / 72 TMF1014 - System Analysis & Design Test Me Solution to Q3 TMF1014 - System Analysis & Design Semester 1, 2018-2019 64 / 72 Remind Me TMF1014 - System Analysis & Design Remind Me HOW to draw/construct a DFD? A Journey to Produce a DFD TMF1014 - System Analysis & Design Semester 1, 2018-2019 66 / 72 TMF1014 - System Analysis & Design Remind Me TMF1014 - System Analysis & Design Semester 1, 2018-2019 67 / 72 TMF1014 - System Analysis & Design Remind Me Rules for Using DFD Symbols Data Flow that connects: TMF1014 - System Analysis & Design Semester 1, 2018-2019 68 / 72 TMF1014 - System Analysis & Design Remind Me Relationship among DFD levels TMF1014 - System Analysis & Design Semester 1, 2018-2019 69 / 72 Point Me TMF1014 - System Analysis & Design Point Me Which Book? Systems Analysis and Design (9th Edition). 2013. Kenneth E. Kendall & Julie E. Kendall. Prentice Hall. TMF1014 - System Analysis & Design Semester 1, 2018-2019 71 / 72 ALL THE BEST! from SA&D Team