Accounts & Finance

"Part (a): Entity-Relationship Diagram (ERD)

The Entity-Relationship Diagram (ERD) for Zenner Collections includes entities for Items, Geographic Areas, Regions, Historical Eras, and Reference Books.

Part (b): Primary and Foreign Keys

Geographic Area

Primary Key: id

Region

Primary Key: id

Historical Era

Primary Key: id

Reference Book

Primary Key: id

Item

Primary Key: id

Foreign Keys: geo_area_id, era_id

Historical_Era_RefBook (Junction Table)

Foreign Keys: era_id, ref_book_id

Part (c): Extended Entity-Relationship (EER)

To classify antique firearms with extra attributes, EER features such as specialization (subclasses) can be used.

Subclasses/Specialization:

Create a subclass for Firearm under the Item entity to capture specific attributes related to firearms.

This subclass can inherit all attributes of the Item entity and have additional attributes specific to firearms, such as license_number, insurance_details, etc."