Common one-to-many table for multiple entities

Question

Suppose I have two tables, Customer and Vendor. I want to have a common address table for customer and vendor addresses. Customers and Vendors can both have one to many ad

Answer 1

How about having four tables with one acting as a gateway to the addresses? So you would have

Customer
    customerId (PK)
    addressBookId (FK to AddressBook)

Vendor
    vendorId (PK)
    addressBokId (FK to AddressBook)

AddressBook
    addressBookId (PK)

Address
    addressId (PK)
    addressBookId (FK to AddressBook)