How to interpret the minimum cardinality in this E-R model? ++ customer *customer_id store_id first_name last_name email address_id active create_date last_update address "address_id address address2 district city_id postal_code phone last_update A customer doesn't need an address, and an address needs to be assoicated with a customer at least. A customer must have an address at least, and an address doesn't need to be assoicated with a customer. A customer can have an address at most, and an address can be assoicated with a customer at most