marți, 24 noiembrie 2009

Quiz: Subtype Mapping


1. Which of the following are reasons you should consider when using a Subtype Implementation? (Choose Two)
When the common access paths for the subtypes are similar.
When the common access paths for the subtypes are different. (*)
Business functionality and business rules are similar between subtypes.
Most of the relationships are at the subtype level (*)
2. When mapping supertypes, relationships at the supertype level transform as usual. Relationships at subtype level are implemented as foreign keys, but the foreign key columns all become optional. True or False?
True (*)
False
3. When translating an arc relationship to a physical design, you must turn the arc relationships into foreign keys. What additional step must you take with the created foreign keys to ensure the exclusivity principle of arc relationships? (Assume that you are implementing an Exclusive Design) (Choose Two)
Make all relationships mandatory
Make all relationships optional (*)
Create an additional check constraint to verify that one foreign key is populated and the others are not (*)
All the above
4. The “Arc Implementation” is a synonym for what type of implementation?
Supertype Implementation
Subtype Implementation
Cascade Implementation
Supertype and Subtype Implementation (*)

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