Dependencies do not imply that a set of steps must be executed to execute the parent process. Rather, they reflect a business state that allows execution of dependent processes.
In the previous illustration, the execution of Customer Ordering does not mean that an execution of Take Order must be followed by an execution of Cancel Order or must Amend Order. Rather, the diagram shows that Take Order can leave the business in a state that enables execution of Cancel Order or can Amend Order. In this situation, Take Order is considered prerequisite to Cancel Order and Amend Order, while Cancel Order and Amend Order depends Take Order.
Take Order has a post-condition that, when true, satisfies the preconditions for either Cancel Order or Amend Order. The dependency line can therefore be thought of as a matching of a post-condition of the prerequisite process to the precondition of the dependent process.
In Selecting Processes for Dependency Analysis, if an execution of Take Order completes successfully, resulting in the creation of an order entity and its attendant order item entities, it becomes possible for the order to be affected by Cancel Order or Amend Order. Thus, "order created" is the post-condition of Take Order that matches the precondition of Amend Order or Cancel Order.
Find that many post-conditions of processes involve a change of state of one or more entities, and that preconditions specify that entities must be in a particular state to enable a process to execute. They later use these state conditions in entity life-cycle analysis, which is described in the chapter "Analyzing Interactions."
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