week 5 quiz
____ relationships occur when there are multiple relationship paths between related entities. a. Redundant b. Duplicated c. Time-variant d. Supertype
a. Redundant
Surrogate primary keys are especially helpful when there is no ____ key. a. foreign b. natural c. primary d. composite
b. natural
One important inheritance characteristic is that all entity subtypes inherit their ____ key attribute from their supertype. a. foreign b. primary c. surrogate d. natural
b. primary
The "____" characteristic of a primary key states that: The selected primary key must not be composed of any attribute(s) that might be considered a security risk or violation. For example, using a Social Security number as a PK in an EMPLOYEE table is not a good idea. a. nonintelligent b. security compliant c. unique values d. preferably single-attribute
b. security compliant
At the implementation level, the supertype and its subtype(s) depicted in the specialization hierarchy maintain a ____ relationship. a. M:N b. 1:M c. 1:1 d. self-referencing
c. 1:1
1. The ____ depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities). a. subtype discriminator b. entity supertype c. specialization hierarchy d. inheritance
c. specialization hierarchy
A(n) ____ is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related. a. specialization hierarchy b. entity supertype c. subtype discriminator d. inheritance discriminator
c. subtype discriminator
Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed only once in the ____ relationship. a. 0:1 b. 1:1 c. 1:M d. M:N
d. M:N
Partial completeness is symbolized by ____. a. a dotted line b. two dashed lines c. a circle over a double line d. a circle over a single line
d. a circle over a single line
The "____" characteristic of a primary key states that: The PK should not have embedded semantic meaning. An attribute with embedded semantic meaning is probably better used as a descriptive characteristic of the entity rather than as an identifier. a. unique values b. security compliant c. preferably single-attribute d. nonintelligent
d. nonintelligent
