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Context Diagram

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Context Diagram

Published in: Business

Context Diagram

  1. 1. CONTEXT DIAGRAM
  2. 2. Context Diagram <ul><li>A DFD that summarizes all processing activity within the system in single process symbol. </li></ul><ul><ul><li>Describes highest level view of a system </li></ul></ul><ul><ul><li>All external agents and all data flows into and out of a system are shown in the diagram </li></ul></ul><ul><ul><li>The whole system is represented as one process </li></ul></ul><ul><ul><li>The data flows that pass between the external entities and the system. </li></ul></ul>
  3. 3. Data Flow Diagram <ul><li>A graphical system model that shows all of </li></ul><ul><li>the main requirements for an information </li></ul><ul><li>system: inputs, outputs, processes and data </li></ul><ul><li>storage </li></ul><ul><li>They are primarily used in the systems </li></ul><ul><li>development process. </li></ul><ul><li>A data flow diagram is often the diagram of </li></ul><ul><li>choice for modern entities. </li></ul>
  4. 4. Purpose <ul><li>To identify and examine the interface between the external entities and the system. </li></ul><ul><li>For Example </li></ul><ul><li>A Context Data Flow Diagram for Payroll Processing </li></ul><ul><li>shows a context diagram for a Payroll Processing that interacts with 5 agents: Employee, Management, Government Agencies, Human Resources, Time keeping. </li></ul>
  5. 6. Symbols used in Context Diagram <ul><li>A square represents an external data </li></ul><ul><li>source or data destination. </li></ul><ul><li>A Vowel indicates a internal entity or </li></ul><ul><li>transformation process. </li></ul><ul><li>A line with an arrow indicates the direction of the flow of data. </li></ul>
  6. 7. Guidelines for drawing a Context Diagram <ul><li>List potential external entities (people, </li></ul><ul><li>places). Look for entities that </li></ul><ul><ul><li>Give data to the system without explaining the process that creates that data </li></ul></ul><ul><ul><li>Take data from the system without explaining what it does with that data </li></ul></ul><ul><li>Establish what flows are sent to and from the </li></ul><ul><li>system from the external entities </li></ul><ul><li>Draw the context diagram </li></ul>

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