How would you check a data model for redundancy? Give an example to illustrate your answer.
What will be an ideal response?
(1) Re-examine one-to-one (1:1) relationships
In the identification of entities, we may have identified two entities that represent the same
object in the enterprise. For example, we may have identified the two entities Client and
Renter that are actually the same; in other words, Client is a synonym for Renter. In this
case, the two entities should be merged together. If the primary keys are different, choose one
of them to be the primary key and leave the other as an alternate key.
A relationship is redundant if the same information can be obtained via other relationships.
We are trying to develop a minimal data model and, as redundant relationships are
unnecessary, they should be removed. It is relatively easy to identify whether there is more
than one path between two entities. However, this does not necessarily imply that one of the
relationships is redundant, as they may represent different associations between the entities.
(3) Consider time dimension The time dimension is important when assessing redundancy.
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Fill in the blank(s) with the appropriate word(s).
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What will be an ideal response?