Database

1.

Based on Figure 2, the superclass (Call) must be a member of at most one of the subclasses (Regular, Long_distance and Cell). Which of the following constraints describe the EER-Model?

Select one:

A.Optional and disjoint

B.Optional and non-disjoint

C.Mandatory and disjoint

D.Mandatory and non-disjoint

2. Before you start the process of logical database design, you need to remove features which are not compatible with logical model. All of the following features have to be removed EXCEPT FOR ________.

Select one:

A.Remove relationship such as ternary

B.Remove one-to-one optional relationship

C.Remove attributes with more than one values

D.Remove many-to-many binary relationship types

Call Customer_id {PK} Date {PK} Time {PK} Destination_No Regular Long distance Cell Counter Duration Carrier_name Duration Air_time Land_time Figure 2