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chapter 3.2 - Coggle Diagram

- - - - Alias
      - Type and length
      - Data element name and label
      - Default value
      - Acceptable values - Domain and validity rules
      - Source
      - Security
      - Responsible user(s)
      - Description and comments
    - - Origin
      - Destination
      - Alternate name(s)
      - Record
      - Description
      - Volume and frequency
      - Data flow name or label
- - - - Receives input data and produces output that has a different content, form, or both
      - Contain the business logic, also called business rules
      - Referred to as a black box
    - - Represents one or more data items
      - The symbol for a data flow is a line with a single or double arrowhead
      - Avoid
        
        Spontaneous generation = process produces output, but has no input data flow
        
        Black hole = process that has input, but produces no output
        
        Gray hole = process that has at least one input and one output, but the data obviously is insufficient to generate the output
      - Data store symbol
        
        Represent data that the system stores
        
        The physical characteristics of a data store are unimportant because you are concerned only with a logical model
      - Entity Symbol
        
        Name of the entity appears inside the symbol
        
        Shows only external entities that provide data to the system or receive output from the system.
  - - - Use unique names within each set of symbols
      - Do not cross lines
      - Use the name of the information system as the process name in the context diagram
      - Provide a unique name and reference number for each process
      - Draw the context diagram so that it fits on one page
      - Obtain as much user input and feedback as possible