The Scholar notes at
https://scholar.hw.ac.uk/courses/content/ahccmp/2/1/2/5/Database-design-and-development__Design__Entity~relationship-diagrams__Relationship-participation
cover relationship participation and contradict the written explanation of the Travel Agency scenario in the AH Course Spec.
I looked into how ER diagrams and relationships used to be described in earlier courses and think I see the source of confusion.
Alternative/earlier ER diagramming techniques showed optional/mandatory relationships that were described differently. The descriptions sometimes followed on from entity occurrence diagrams that concluded that, for example, if a Resort could occur without a corresponding Hotel, then Resort was optional. Similarly, if a Hotel could not occur without a corresponding Resort, then Hotel was mandatory.
A diagram for this might be show as
Resort – —–< Hotel
where the broken line shows that the relationship was optional at the Resort end (a Resort may have an associated Hotel) and mandatory at the Hotel end (a hotel must have an associated Resort).
Now, at AH, this relationship would be shown as
Resort -|—-O< Hotel
and the description/terminology used has changed direction. E.g. If a Resort could occur without a corresponding Hotel then Hotel’s participation in the relationship is optional. Similarly, if a Hotel could not occur without a corresponding Resort, then Resort’s participation in the relationship is mandatory.
The notes in the AH Course Spec introduce ‘relationship participation’ using the new diagram style and terminology but explain the Travel Agency example using the old. Also, the marking schemes for the specimen paper and the 2020 paper use the new diagram style but the older approach to determine which end is optional and which is mandatory.
I like the Scholar material and am (now) using it with my AH group this year.