Practice Paper Part 3 Q3

[seadragon2000341]

Hi!

I was also wondering why for this question, the last option is not compliant?

Also for the 4th option, why is it compliant since there
i) is no mention of Activity referencing another activity
ii) I am not too sure about the composition - does it mean that an activity cannot exist without another activity? But I dont see any part that suggests this

Thank you!

[damithc]

Related point: one should show an association as a line or an attribute, but not both.

[muhammadreyaaz]

I feel like even if the role is not stated (since it is optional), the navigability arrow shows that there is a duplicate association (shown as both line and attribute.) So that is the reason I think it is not correct, which prof @damithc mentioned as a related point.

[damithc]

I feel like even if the role is not stated (since it is optional), the navigability arrow shows that there is a duplicate association (shown as both line and attribute.) So that is the reason I think it is not correct, which prof @damithc mentioned as a related point.

Yes, that's correct. Thanks @ARPspoofing

[jiasheng59]

(ii) I think this is based on how you interpret the "subactivities" relationship. My understanding for this is that a activity (you can treat it as an event) consists of multiple smaller activities.

Moreover, it's meaningless for these smaller activities to exist without the single event. I mean, this doesn't really imply whole-part relationships but at least you should observe this property if you want to convince yourself that it's a composition.

[jiasheng59]

I hope I don't mislead you that delete cascading leads to identifying it as composition relationship.

Just to be clear, it's a necessary condition, not a sufficient condition