Level n diagram proposed physical level 1 diagram

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Level n Diagram Proposed Physical Level 1 Diagram Process 1 1.2 Check for Availability (automated) 1.1 Check Prerequisites Met (automated) 1.3 Enroll Student in Class (automated) D1 Semester Enrollment DB D5 Course Catalogue DB D4 Registrar’s Student DB D3 Semester Schedule DB Class Request (verbal) Authorized Class Request Valid Class Request Open Seats Available Seats Student and Course Data Student Notified (email) Student Alerted (email) Student Record Course Record
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Use Case as Starting Point DFDs start with the information in the use cases and the requirements definition. Generally, the set of DFDs integrates the individual use cases. The project team takes the use cases and rewrites them as DFDs, following the DFD formal rules about symbols and syntax. CASE tools are used to draw actionable draw process models.
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Use Case as Starting Point Value to map out and understand Key user interactions with the system Preconditions, post conditions Events, triggers Actors Usual, alternative, and erroneous operation Inputs (w/ sources) Outputs (w/ sinks)
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Use Case as Starting Point 1. Build the context diagram. 2. Create DFD fragments for each use case. 3. Organize the DFD fragments into level 0 diagram. 4. Develop level 1 DFDs based on the steps with each use case. In some cases, these level 1 DFDs are further decomposed into level 2 DFDs, level 3 DFDs., and so son. 5. Validate the set of DFDs to make sure that they are complete and correct.
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Creating the Context Diagram The context diagram defines how the business process or computer system interacts with its environment. Draw one process symbol for the business process or system being modeled (numbered 0 and named for the process or system). Add all inputs and outputs listed on the form of the use cases as data flows. Draw in external entities as the source or destination of the data flows. No data stores are included in the context diagram.
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37 Creating the Context Diagram
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Class Exercise Perform a quick use-case analysis and design a context level diagram for one of these examples: - Self-serve grocery checkout (e.g., Giant) - EZPass tag reader/billing system - RMA system for online orders - Payroll system - Package tracking system (e.g., USPS) - Cable TV billing system (regular & pay-per-view) - UMBC ID card-based vending machine - Online florist delivery system - Metro / subway card - Your choice… Please label your two drawings with the names of those who actively participated and turn in at the end of class.
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