Requirements Analysis Using Event/Response and Use Cases – Event Discovery Part 3

Planning

This is the third part in the series on Event discovery. In the first two parts I covered discovering Events using the Context Diagram and the Outputs listed on the Event List. In this post, I will cover using a technique known as “State-Transition”.

In specific cases of analysis where there is a central entity that moves to a variety of “states” during its life, the State-Transition diagram can be very useful in discovering Events. Let us take the example of a retail product where the project sponsor wishes to track the product in all of its possible states. The following are possible examples of the states of this product:

  • Designed
  • Ordered]
  • Manufactured
  • Shipped / In-Transit
  • Arrived at Distribution Center
  • In Inventory
  • Allocated to Store
  • Packed
  • Shipped to Store
  • Arrived in Store
  • Available for Sale
  • Sold

Each of these states has a corresponding Event that causes the product to transition from one state to the next. For example, the transition from “In Inventory” to “Allocated to Store” could be triggered by the data event “Store Inventory Level for this Product drops below reorder point”. Now that you have the Event, you can fill in the rest of the row on the Event List in discussion with the SME’s (Subject Matter Experts).

Note that it is possible and allowed for an Entity in a given State to transition to more than one possible State, depending on the Event. For example, an Employee can transition to a new job (via promotion or transfer) or transition to full-time or part-time, or transition to terminated.

Knowing all of the relevant States of an Entity can be very useful to filling out the Event List in certain analysis situations.

In the next post, I will present another Event discovery technique involving the life cycle of key Entities.

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Requirements Analysis Using Event/Response and Use Cases – Event Discovery Part 2

Planning

In the previous post I discussed how to use the Context Diagram for initial Event discovery. In this post I will present how to use the outputs from your Event List to discover more events.

The fifth column in your Event List (the one labeled “Which creates this…”) are the outputs of your business processes. You can use these outputs to discover more Events by asking the following questions for each output:

  • Does the output go to a “Customer”? (an entity outside of the center bubble in the Context Diagram). If yes, then that is where the output ends. If no, then that means it must be input to another event or the output has no purpose. Ask your SME’s (Subject Matter Experts) what other business processes use this data. For each identified business process, you can flesh out the Event List row for that process.
  • What are the “Create” Events for this output? These are the Events that result in the establishment of a new row (or rows) of data in the output in question. For example, the sale of a product creates a Sales Transaction record. Note there may be more than one Event that creates rows in this output.
  • What are the “Change” Events for this output? For this you may need to examine each data element in the output. For each element, ask the SME’s what business processes change this data. Use these answers to continue to build the Event List.
  • What are the “Delete” Events for this output? These are the Events that result in the logical or physical removal of a row in the output. For example, if the record retention requirement for the output is 5 years, then the time-based event “Record Retention Limit Reached” will be added to your Event List.

Now that you have added many more rows to your Event List, you will have more outputs to examine. Cycle back thru the Event List outputs and ask the same questions listed above. You will find your Event List grows very quickly!

In the next post I will continue to present additional techniques for Event Discovery.

Requirements Analysis Using Event/Response and Use Cases – Event Discovery Part 1

Planning

In prior posts I introduced the Context Diagram and the Event List. In this and the upcoming series of posts, I will define some techniques you can use to discover events and complete the Event List and Context Diagram.

The very first place to start defining events is the Context Diagram. Every input arrow on the diagram represents an event to which your “business” must respond. Remember, our definition of your “business” is the boundary of the business area under study. Inside of the business bubble on the Context Diagram, you have control over the business processes and data flows. Outside the boundary, you can negotiate the interfaces with the Suppliers and Customers but have little or no control over their business processes.

Let’s examine an example of how the Context Diagram can provide events. For this example, let us say the Supplier is an Employee and the input arrow is “Travel Expense Details”.

Our first column on the Event List is “When this happens”. In this example, you would state “Travel Expense Report Submitted”.

The second and third columns are “This Source” and “Gives us This”. In this example, the Source is “Employee”, and “Gives us This” is “Travel Expense Details”.

The fourth column is “Then we do this”. These are the labels of the business processes your “business” will execute upon receipt of the “Travel Expense Details”. You might have a list of processes that looks like this:

  • Verify expenses comply with business policy
  • Approve/Reject Expenses

The fifth column is “Which creates this”. These are the outputs of each business process. The outputs of the first process listed above might be “Valid Expenses” and “Invalid Expenses”. The outputs of the second process listed above might be “Approved Expenses” and “Rejected Expenses”.

The sixth column is “… and we give it to …”. These are the recipients of the outputs listed in the fifth column. In this case the recipient of the Valid and Invalid Expenses could be “Employee’s Manager”. The recipient of “Rejected Expenses” would be the Employee while the recipient of “Approved Expenses” could be the Travel Expense Data Repository.

In the next post, I will continue the discussion of Event Discovery and show how, once you have a few events listed, you can use these events to discover more events and get the complete scope of the project.