CS6400 EXAM SCRIPT VERIFIED
QUESTIONS WITH FULL SOLUTION
●● How to map a single value property, B, in a relation, ET?
Answer: ET will have B as an attribute
●● How to map an identifying property, A, in a relation, ET?
Answer: A becomes the primary key of ET
●● How to map a composite property type, C composed of D and E, in a
relation, ET?
Answer: ET will have D and E as attributes
●● What happens to composite property C when mapping to relations?
Answer: C gets lost and the meaning expressed by the relation is not as
rich.
By putting C in the relation, it loses the property of having atomic
relations.
●● How to map a multivalued property type, F, in a relation, ET?
Answer: Create a new relation, ET-F.
,The combination of A and F become a composite key
A is a foreign key
For a given instance of ET, it will have a unique value of A.
●● How to map 1:1 relationship types with entities ET1 (PK A) and ET2
(PK B)?
Answer: In either relation, add the PK of the other entity as a foreign key
●● How to map 1:1 relationships with mandatory participation?
Answer: Put the foreign key on the mandatory side so that for every
instance of the mandatory participation side, it is related to the other
entity.
●● How to map 1:M relationship types?
Answer: Assign the foreign key to the "many" side
●● How to map N:M relationship types?
Answer: Create a relation for ET1
Create a relation for ET2
, Create a relation for the relationship between ET1 and ET2, which has
FK to PK of ET1 (A) and another FK to PK of ET2 (B)
●● How to map weak relationships? ET1 is strong entity, ET2 is weak
entity
Answer: Create a relation ET1 with PK (A)
Create a relation ET2 with composite PK, A and B.
A is an FK to ET1 in ET2
●● How to map super-subtype relationships (mandatory/disjoint)?
ET is supertype
ET1 and ET2 are subtypes
Answer: Create a relation for ET1 and ET2 with attributes of ET
●● How to map super-subtype relationships (mandatory/overlap)?
ET is supertype
ET1 and ET2 are subtypes
Answer: Create a relation ET
QUESTIONS WITH FULL SOLUTION
●● How to map a single value property, B, in a relation, ET?
Answer: ET will have B as an attribute
●● How to map an identifying property, A, in a relation, ET?
Answer: A becomes the primary key of ET
●● How to map a composite property type, C composed of D and E, in a
relation, ET?
Answer: ET will have D and E as attributes
●● What happens to composite property C when mapping to relations?
Answer: C gets lost and the meaning expressed by the relation is not as
rich.
By putting C in the relation, it loses the property of having atomic
relations.
●● How to map a multivalued property type, F, in a relation, ET?
Answer: Create a new relation, ET-F.
,The combination of A and F become a composite key
A is a foreign key
For a given instance of ET, it will have a unique value of A.
●● How to map 1:1 relationship types with entities ET1 (PK A) and ET2
(PK B)?
Answer: In either relation, add the PK of the other entity as a foreign key
●● How to map 1:1 relationships with mandatory participation?
Answer: Put the foreign key on the mandatory side so that for every
instance of the mandatory participation side, it is related to the other
entity.
●● How to map 1:M relationship types?
Answer: Assign the foreign key to the "many" side
●● How to map N:M relationship types?
Answer: Create a relation for ET1
Create a relation for ET2
, Create a relation for the relationship between ET1 and ET2, which has
FK to PK of ET1 (A) and another FK to PK of ET2 (B)
●● How to map weak relationships? ET1 is strong entity, ET2 is weak
entity
Answer: Create a relation ET1 with PK (A)
Create a relation ET2 with composite PK, A and B.
A is an FK to ET1 in ET2
●● How to map super-subtype relationships (mandatory/disjoint)?
ET is supertype
ET1 and ET2 are subtypes
Answer: Create a relation for ET1 and ET2 with attributes of ET
●● How to map super-subtype relationships (mandatory/overlap)?
ET is supertype
ET1 and ET2 are subtypes
Answer: Create a relation ET
