In which database model can objects have multiple parents?

What are variables?

What will be an ideal response?

The schema of the Student Registration System includes the number of current registrants and a list of registered students in each course.

a. What integrity constraint relates this data? b. Howmight a registration transaction that is not atomic violate this constraint? c. Suppose the system also implements a transaction that displays the current information about a course. Give a nonisolated schedule in which the transaction displays inconsistent information.