Use of a supertype/subtype relationship is necessary when which of the following exists?
A. An instance of a subtype participates in a relationship that is unique to that subtype.
B. An instance of a subtype participates in a relationship that is the same as the other subtypes.
C. Attributes apply to all of the instances of an entity type.
D. No attributes apply to any of the instances of an entity type.
Answer: Option A
This Question Belongs to Database >> ER Model And Business Rules
An action assertion must include which of the following?
A. Anchor object
B. Action
C. Corresponding object
D. All of the above
An oval represents which of the following in an EER?
A. Attribute
B. Entity
C. Optional One
D. Relationship
Inheritance is which of the following?
A. When a supertype entity inherits values of the subtype attribute
B. When a subtype entity inherits values of the supertype attribute
C. When a supertype entity inherits values of another supertype attribute
D. When a subtype entity inherits values of another subtype attribute
When an entity instance must be a member of only one subtype, it is which of the following?
A. Disjoint with total specialization
B. Disjoint with partial specialization
C. Overlap with total specialization
D. Overlap with partial specialization
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