Archive for December 17th, 2007

Describe an entity cluster.

Monday, December 17th, 2007

The key to this answer is understanding that an ENTITY CLUSTER is actually a “virtual” entity type and that the entity cluster is formed by combining into a single abstract object multiple entities that are related to one another. This abstract entity object is not a single entity as documented in the final ERD.

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When is denormalization preferred to normalization?

Monday, December 17th, 2007

When performance issues outweigh design considerations. Sometimes too much normalization can slow down performance.

 

If the candidate understands this concept it’s a good thing… if not, you have an issue.

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