A dangling pointer is a reference to a data object or resource that no longer exists. In resource APIs, deleting an author while books still store its authorId creates one. section 13.3.2
Deletion policies trade convenience, consistency, and operational cost:
- Restrict deletion and return an error, preserving references but potentially forcing consumers to delete many dependent resources. section 13.3.2 section 14.3.6
- Set references to null, avoiding invalid pointers but risking large, slow, or non-atomic update operations. section 13.3.2 section 14.3.6
- Cascade deletion, or do nothing and leave consumers to handle invalid references; both can trigger substantial downstream effects. section 14.3.6
Deleting a referenced author
Create an author named Michelle Obama, create the book Becoming with authorId set to that author's id, then delete the author. The book now contains a dangling pointer unless the API restricts, clears, cascades, or explicitly tolerates the invalid reference. section 13.3.2
