February 26, 2009

Data Modeling Tricks

Developing a good entity definition is more than just an exercise in documentation. Good entity definitions are essential to the identification and demarcation of the set of entities in a . To do this, each entity definition needs to be intentional1; that is, comprising a comprehensive set of criteria that an instance must meet in order to be distinguishable as a member of the entity set. An extentional definition, in contrast, is a list of examples. An extentional definition may provide good additional clarification for the “real,” intentional definition; but, by definition (ahem), an intentional definition cannot be comprehensive.

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Posted by tonyr at 12:49 PM