In spelunking the Vista database, the main pieces of an enrollment are the user, the learning context, the membership, the role, and the role’s label. Its almost trivial how easily these tie together. Once you have them, then you can do all kinds of cool things…

• Administrator reports Section Designer role was deleted but the Build tab is still showing. So, you dump out the user’s enrollments to confirm the role was in fact deleted. It turns out the user had a Designer role at a higher context. [1]
• Instructor reports students who were never enrolled in the section appear as having missed an assignment. Support at the school says the it has a template, so naturally the vendor thinks it must be a bad template. Wait, you say, I didn’t think student data was part of the template. That changes everything! So, you dump out the enrollments for the members of that learning context to see who is or is not enrolled. Oh, the students were enrolled in the class. They are just deleted now.

[1] Designer access at a higher level means the Build tab shows. So if you hold Institution Designer and Section Instructor, then you have the Build tab you’d normally expect to need Section Designer to use.