CS6400 - Exam 2 QUESTIONS WITH |\ |\ |\ |\ |\ |\
ANSWERS
How to map entity types? - CORRECT ANSWERS ✔✔Create a
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relation for the entity type with the same name
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How to map a single value property, B, in a relation, ET? -
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CORRECT ANSWERS ✔✔ET will have B as an attribute
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How to map an identifying property, A, in a relation, ET? -
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CORRECT ANSWERS ✔✔A becomes the primary key of ET
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How to map a composite property type, C composed of D and E,
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in a relation, ET? - CORRECT ANSWERS ✔✔ET will have D and E
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as attributes
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What happens to composite property C when mapping to
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relations? - CORRECT ANSWERS ✔✔C gets lost and the meaning
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expressed by the relation is not as rich. |\ |\ |\ |\ |\ |\ |\
By putting C in the relation, it loses the property of having atomic
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relations.
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How to map a multivalued property type, F, in a relation, ET? -
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CORRECT ANSWERS ✔✔Create a new relation, ET-F.
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The combination of A and F become a composite key
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,A is a foreign key
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For a given instance of ET, it will have a unique value of A.
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How to map 1:1 relationship types with entities ET1 (PK A) and
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ET2 (PK B)? - CORRECT ANSWERS ✔✔In either relation, add the
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PK of the other entity as a foreign key
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How to map 1:1 relationships with mandatory participation? -
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CORRECT ANSWERS ✔✔Put the foreign key on the mandatory |\ |\ |\ |\ |\ |\ |\ |\ |\
side so that for every instance of the mandatory participation
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side, it is related to the other entity.
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How to map 1:M relationship types? - CORRECT ANSWERS
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✔✔Assign the foreign key to the "many" side |\ |\ |\ |\ |\ |\ |\
How to map N:M relationship types? - CORRECT ANSWERS
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✔✔Create a relation for ET1 |\ |\ |\ |\
Create a relation for ET2 |\ |\ |\ |\
Create a relation for the relationship between ET1 and ET2, which
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has FK to PK of ET1 (A) and another FK to PK of ET2 (B)
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How to map weak relationships? ET1 is strong entity, ET2 is weak
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entity - CORRECT ANSWERS ✔✔Create a relation ET1 with PK (A)
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, Create a relation ET2 with composite PK, A and B.
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A is an FK to ET1 in ET2
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How to map super-subtype relationships (mandatory/disjoint)?
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ET is supertype
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ET1 and ET2 are subtypes - CORRECT ANSWERS ✔✔Create a
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relation for ET1 and ET2 with attributes of ET
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How to map super-subtype relationships (mandatory/overlap)?
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ET is supertype
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ET1 and ET2 are subtypes - CORRECT ANSWERS ✔✔Create a
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relation ET |\
Create a relation ET1 that has ET's PK as its PK and an FK to ET
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Create a relation ET2 that has ET's PK as its PK and an FK to ET
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How to map super-subtype relationships
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(nonmandatory/overlap)?
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ET is supertype
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ANSWERS
How to map entity types? - CORRECT ANSWERS ✔✔Create a
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
relation for the entity type with the same name
|\ |\ |\ |\ |\ |\ |\ |\
How to map a single value property, B, in a relation, ET? -
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
CORRECT ANSWERS ✔✔ET will have B as an attribute
|\ |\ |\ |\ |\ |\ |\ |\
How to map an identifying property, A, in a relation, ET? -
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
CORRECT ANSWERS ✔✔A becomes the primary key of ET
|\ |\ |\ |\ |\ |\ |\ |\
How to map a composite property type, C composed of D and E,
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in a relation, ET? - CORRECT ANSWERS ✔✔ET will have D and E
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as attributes
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What happens to composite property C when mapping to
|\ |\ |\ |\ |\ |\ |\ |\ |\
relations? - CORRECT ANSWERS ✔✔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? -
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
CORRECT ANSWERS ✔✔Create a new relation, ET-F.
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The combination of A and F become a composite key
|\ |\ |\ |\ |\ |\ |\ |\ |\
,A is a foreign key
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For a given instance of ET, it will have a unique value of A.
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How to map 1:1 relationship types with entities ET1 (PK A) and
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
ET2 (PK B)? - CORRECT ANSWERS ✔✔In either relation, add the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
PK of the other entity as a foreign key
|\ |\ |\ |\ |\ |\ |\ |\
How to map 1:1 relationships with mandatory participation? -
|\ |\ |\ |\ |\ |\ |\ |\ |\
CORRECT ANSWERS ✔✔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? - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔Assign the foreign key to the "many" side |\ |\ |\ |\ |\ |\ |\
How to map N:M relationship types? - CORRECT ANSWERS
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✔✔Create a relation for ET1 |\ |\ |\ |\
Create a relation for ET2 |\ |\ |\ |\
Create a relation for the relationship between ET1 and ET2, which
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has FK to PK of ET1 (A) and another FK to PK of ET2 (B)
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How to map weak relationships? ET1 is strong entity, ET2 is weak
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entity - CORRECT ANSWERS ✔✔Create a relation ET1 with PK (A)
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, Create a relation ET2 with composite PK, A and B.
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A is an FK to ET1 in ET2
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How to map super-subtype relationships (mandatory/disjoint)?
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ET is supertype
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ET1 and ET2 are subtypes - CORRECT ANSWERS ✔✔Create a
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relation for ET1 and ET2 with attributes of ET
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How to map super-subtype relationships (mandatory/overlap)?
|\ |\ |\ |\ |\
ET is supertype
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ET1 and ET2 are subtypes - CORRECT ANSWERS ✔✔Create a
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
relation ET |\
Create a relation ET1 that has ET's PK as its PK and an FK to ET
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Create a relation ET2 that has ET's PK as its PK and an FK to ET
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How to map super-subtype relationships
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(nonmandatory/overlap)?
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ET is supertype
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