A primary action sequence is the normal ordered set of interactions between the triggering actor, other actors, and the application during a use case. Write it from the triggering actor’s point of view, keeping it to about ten steps; a longer sequence may indicate excessive complexity. section 3.6.2
A practical sequence should:
- Begin after the actor’s trigger and describe the normal action steps in order. section 3.6.2
- Allow steps to refer to other use cases when the interaction is reusable or complex. section 3.6.2
- Stay separate from alternate action sequences, which describe what happens when something goes wrong. section 3.6.2
Searching a catalogue
A customer submits target book attributes through an online form, and the catalogue returns matching books. The sequence belongs to the Search Catalogue use case and assumes that books and attributes are already loaded. section 3.6.2
