Deletion Policy, Serialization Function, and Object-to-Storage

Deletion policy

We have to choose and implement one of two possible deletion policies that manage the corresponding object destruction dependency in the destroy method of the property’s range class for any reference property. In our case, when deleting a publisher record, we have to choose between the following actions:

1. Delete all records of books published by the deleted publisher. This is known as existential dependency.

2. Drop the reference to the deleted publisher from all books by the deleted publisher. This is known as existential independence.

Assuming that books don’t existentially depend on their publishers, we choose the second option. The following code shows the Publisher.destroy method which means that for all concerned book objects, the property book.publisher is cleared.