M. Rasti-Barzoki rasti.iut.ac.ir Management Information Systems

Transcription

1 M. Rasti-Barzoki Management Information Systems

2 : Data Flow Diagram PFD: Process Flow Diagram (PM: Process Model) FHD: Function Hierarchy Diagram DT: Decision Table 2

3 Entity Attribute 3

4 Data Elements The descriptive property or characteristic of an entity. In database terms, this is a "attribute" or a "field." 4

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6 Where who when What What 6

7 Context Diagram A data flow diagram () of the scope of an organizational system that shows the system boundaries, external entities that interact with the system and the major information flows between the entities and the system Level-O Diagram A data flow diagram () that represents a system s major processes, data flows and data stores at a high level of detail 7

8 Elements 8

9 Elements 9

10 Source & Destination Internal & External Entity Process Data Flow Data store 10

11 Symbology Process 6.1 امانت کتاب Data Store دانشجو فايل D7 Entity دانشجويان Data Flow اطالعات مشتري جديد DeMarco-Yourdon Symbology Gane-Sarson Symbology Examples 11

12 حسابهاي بانکي 12

13 Elements 13

14 » 14

15 Symbology 15

16 Elements 16

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18 M Decomposition of Context Diagram 0 P Context Diagram N M D1 1 2 Level-0 Diagram P N 3 Level-1 Diagram 18

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21 »»»»» 21

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23 Rules for Drawing s A minimum of one data flow in and one data flow out of a process A datastore must be connected to a process (either in, out, or both) An external entity must be connected to a process (either in, out, or both) 23 A single data flow must only flow one way

24 : Common Mistakes Process has no data flowing into it, but has data flowing out. Data store is hooked to external entity. This means external entity can read and write to your data file without auditing!! The data flow goes in two directions at once. Two or more arrows should be used to show the flow to and from each process. 24

25 Elements 25

26 دز يک زست زان اش يک سيستم اطالعاتي استفاد مي ش د ک سفازش غرا زا اش مشتسيان گسفت ب آشپصخاو ازسال کسد ي ب کىتسل م ج دي مي پسداشد. بعالي سيستم گصازشاتي بساي مديسيت ايجاد مي کىد. الشم ب ذکس است ک سيستم اطالعات ميصان م ج دي ي اطالعات کاال اي فسيخت شد زا ذخيس کسد ي اش آن ا دز ت ي گصاشات مديسيتي استفاد مي کىد. بساي سيستم ف ق وم داز محت ا Digram( )Context تسسيم کىيد. بساي سيستم ف ق وم داز جسيان داد سطح 0 تسسيم کىيد )زا ىمايي: 5 فسايىد(. 26

27 Context diagram of Hoosier Burger s Food ordering system 27

28 Level-0 of Hoosier Burger s food ordering system 28

29 شسکت A يک شسکت ت ليدي دز شميى ل اشم خاوگي مي باشد. شماوي ک مشتسي اش طسيك يب سايت شسکت سفازش مي د د سيستم ب بسزسي م ج د ب دن کاالي م زد وظس دز اوباز شسکت مي پسداشد ي گصازشي دز ايه م زد ب مشتسي مي د د. بعالي سيستم پس اش ذخيس ساشي سفازش آن زا ب ياحد اوباز ازسال مي کىد. شماوي ک کاالي م زد وظس اش اوباز بساي مشتسي ازسال شد اوباز تأييدي ازسال زا ب سيستم ازائ کسد ي سيستم ص زتحسابي بساي مشتسي ازسال ي ذخيس مي کىد. بعالي سيستم گصازشي اش س خسيد ي ص زتحساب ايجاد کسد ي ب ياحد حسابدازي شسکت ازائ مي کىد. بساي سيستم ف ق وم داز مف مي جسيان داد Digram( )Context تسسيم کىيد. )زا ىمايي: 5 فسايىد(. بساي سيستم ف ق وم داز جسيان داد سطح 0 تسسيم کىيد 29

30 Entities Customer Warehouse Accounting Processes 1.0 Check Status 2.0 Issue Status Messages 3.0 Generate Shipping Order 4.0 Manage Accounts Receivable 5.0 Produce Reports Data Stores D1 Pending Orders D2 Accounts Receivable 30

31 Data Flows Order In-Stock Request Order Data Status Data Status Message Shipping Order Order Data Invoice Shipping Confirmation Payment Accounting Data Accounts Receivable Data Order Data Inventory Reports 31

32 Order CUSTOMER Payment In-Stock Request WAREHOUSE Status Message Invoice 0 Order System Shipping Order Shipping Confirmation Inventory Reports ACCOUNTING 32

33 Order In-Stock Request CUSTOMER WAREHOUSE Status Message Status Data 1.0 Check Status Shipping Order Shipping Confirmation 2.0 Issue Status Messages D1 Order Data Pending Orders Order Data 3.0 Generate Shipping Order Payment 4.0 Invoice Accounting Data D2 Manage Accounts Receivable Accounts Receivable Order Data Accounts Receivable Data Inventory Reports 5.0 Produce Reports ACCOUNTING 33

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38 Important Considerations When Constructing s Keep focus on modelling flow and storage of data Identify processes that transform data Maintain the balance between diagrams Assess the need for decomposition Follow conventions to name elements Think of data flows as data in motion Think of data stores are as data at rest Think of processes as actions performed on data Do not worry about how data is produced or used by the external entities 38

39 PFD: Process Flow Diagram (Process Model: PM) 39

40 Process Flow Diagram 40

41 FHD: Function Hierarchy Diagram FHD 41

42 Decision Table & Decision Trees 42

43 Decision Tables Often are the best way to describe a complex set of conditions 43

44 Decision Table Example 44

45 Decision Tables (Continued) Decision tables help analysts ensure completeness and accuracy. Four main problems that can occur in developing decision tables: Incompleteness. Impossible situations. Contradictions. Redundancy. 45

46 Redundancy and Contradictions 46

47 Impossible Situation 47

48 Decision Tree Process Description Tools Graphical representation of the conditions, actions, and rules found in a decision table Whether to use a decision table or tree often is a matter of personal preference 48

49 Drawing Decision Trees First, identify all conditions and actions and the order and timing of these (if they are critical). Second, begin building the tree from left to right while making sure you are complete in listing all possible alternatives before moving over to the right. 49

50 Decision Tree Example 50

51 Decision Tree Advantages Three advantages over a decision table are: The order of checking conditions and executing actions is immediately noticeable. Second, conditions and actions of decision trees are found on some branches but not on others. Third, compared to decision tables, decision trees are more readily understood by others in the organization. 51

52 Pseudo-code 52

53 Structured English (cont.) Posesses the three standard control constructs of: Sequences: represent actions taking place in sequence without interruption. They are defined by the successive appearance of a set of primitive actions Selections: describe a series of alternative policies from which only one is selected IF <condition> CASE ELSE <statement> WHEN <condition> <statements> WHEN <condition> <statements> <statement>..... Iterations: A policy or series of actions is repeated within some bounds. Represented by DO WHILE construct or a REPEAT UNTIL construct 53

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55 رسول اکرم صلي اهلل عليه و اهل: ا فض ل االعمال ا لح ب ف ي اهلل و ا لب غ ض في اهلل با فضيلت رتين اعمال دوستي رد راه خدا و د شمني رد راه اوست.