September 29, 2022

Initial Structural Model - What not to include


  1. Never put navigation arrows in an initial structural model, which is static in nature. Navigation is a dynamic event and concerns the location of objects.
  2. The associated text must not include any reference, within a class description, to another class. For example:

    Class: Sale
    date "The date of the sale."

    This is correct. It is an attribute of the class that is specified in the NSR. The Sale class can be said to have a responsibility to record the date information. This is a passive, static responsibility and does not require the sending of a message from a Sale instance to any other object.

    buyerName "The name of the buyer"

    is incorrect. It is a reference to a property of the Buyer class. Its inclusion can only be determined by the consideration of dynamic aspects of the system. It may be required, but not as part of the initial (static) structural model.
  3. Do not include an orchestrating class, e.g. QuadAdmin. This is will be required later, when looking analysing use cases.
  4. Avoid duplicating the names of associations. In UML two associations can have the same name if they are not between the same two classes. It is sensible to make all association names different, simply because you can identify which association you are talking about by just giving its name. The triple,
    <association name, class name 1, class name 2>
    should identify a unique association. Consequently, the rule is that you must not give two associations, between the same two classes, the same name.


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