14.1. Schema Equivalence and Optimization

Previous chapters discussed how to model the structure of an application in terms of a conceptual schema, and then map it to a logical schema for implementation in a relational database system. Although much of the design and mapping can be automated, humans are required to perform CSDP step 1, since verbalizing the relevant facts about the real world involves human understanding. Given the informal nature of this initial step in modeling the UoD, it is not surprising that people often come up with different ways of describing the same reality.

Hence the same business domain may be modeled by more than one conceptual schema. Moreover, the same conceptual schema may be mapped in different ways to a logical ...

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