A primary action sequence is the expected ordered set of interactions during a use case, written from the triggering actor’s point of view. It connects that actor, other actors, and the application after the trigger occurs. section 3.7.2
Use a primary action sequence to make a use case practical and bounded:
- Describe the actions that occur after the trigger and during the use case. section 3.7.2
- Keep the sequence to about 10 steps; split the use case when it needs more. section 3.7.2
- Refer to other use cases when a step represents reusable behavior, and describe failures separately as alternate action sequences. section 3.7.2
Searching a catalogue
A customer fills out an online form with target book attributes and selects Search. The catalogue then returns books matching those attributes, with the customer and backend database acting as participants. section 3.7.2
