31 2 store customer data customer information d1

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31 2 Store Customer Data Customer Information D1 Customer Data D2 Customer Preferences Customer Data Customer Preferences 2 Store Customer Data Customer Information D1 Customer Data D2 Customer Preferences Customer Data Customer Preferences
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32 2 Store Customer Data Customer Information D1 Customer Data D2 Customer Preferences Customer Data Customer Preferences 2 Store Customer Data Customer Information D1 Customer Data D2 Customer Preferences Customer Data Customer Preferences 2 Extract Customer Preferences Customer Data
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33 D1 Customer Data Customer Data Customer 2.0 Store Customer Data D1 Customer Data Customer Data Customer Information Customer
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Syntax Rules: Source/Sink Must have a unique identifier (label) Label should be a noun phrase Entities external to the system Usually a person, organization or other information system No data flows directly between sources/sinks Such a data flow is not of interest (out of scope), OR There is a process that moves the data Source/ Sink
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35 0 Medical Billing System Doctor Patient Diagnosis Service Information Invoice
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Syntax Rules: DataFlow Must have a unique identifier (label) Label should be a noun phrase Data flows are always unidirectional A data flow may fork, delivering exactly the same data to two different destinations Two data flows may join to form one, only if the original two are exactly the same Bundling at higher levels, details at lower levels. No recursive data flows A data flow to a data store is a ‘write’ and from is a ‘read’ Data Flow
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37 2.0 Total Daily Sales 1.0 Take Customer Order 3.0 Print Delivery Instructions Customer Order Order Information Order Total 2.0 Total Daily Sales 1.0 Take Customer Order 3.0 Print Delivery Instructions Order Information Order Total
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38 2.0 Lookup Customer Record 1.0 Take Customer Order 3.0 Print Delivery Instructions Customer Order Customer Address Customer Information 2.0 Lookup Customer Record 1.0 Take Customer Order 3.0 Print Delivery Instructions Customer Order Customer Address
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39 1.0 Calculate Weekly Sales Daily Sales Cumulative To-Date Sales
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Guidelines Every object in a DFD has a unique name The inputs to a process must be different from the outputs (processes are transformational) Avoid crossing data flows, but if not can “jump” Can repeat data stores, sources, sinks to facilitate drawing. If so, use the following notation: Source/ Sink # Data Store “Jump” in a DFD.
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41 1.0 Validate Customer Data Customer Data Customer Data 1.0 Validate Customer Data Customer Data Valid Customer Data
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42 2.0 Take Customer Order 1.0 Get Customer Data 3.0 Process Customer Order Customer Data Customer Data Order 2.0 Take Customer Order 1.0 Get Customer Data 3.0 Process Customer Order Customer Data Order
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43 1.0 Get Customer Data 2.0 Take Customer Order 3.0 Validate Customer Data Customer Data Only if these are exactly the same Customer Data
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44 1.0 Get Customer Data 2.0 Take Customer Order 3.0 Validate Customer Data Customer Data Preferred notation if truly identical…
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Guidelines Law of Conservation of Data: 1.) Data at rest stay at rest until moved by a process.
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  • Fall '08
  • Koru,G

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