Entity-relationship diagram for a library management system modeling Books and Magazines as subtypes of an abstract Item entity. The schema captures relationships between Members, Libraries, and Items, with Books tracking issuance status and assignment to Members. This design demonstrates inheritance hierarchies and optional relationships, essential for systems managing heterogeneous catalog items with member borrowing workflows. Fork this diagram on Diagrams.so to customize entity attributes, add constraints, or extend with additional item types like DVDs or journals. The optional issued-to relationship allows modeling both checked-in and checked-out inventory states.