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Chapter 7: PRECISE DATA INTEGRITY RULES > PRECISE DATA INTEGRITY RULE PRINCIPLE... - Pg. 292

Data Resource Simplexity __________________________________________________ nested within Employee because it has another parent data entity and it has a subordinate data entity. Deductions could be nested within Pay Check . However, the possibility that another data entity may want to access Deductions means it is best to place the deductions in their own data file. The second exception is denormalization of third normal form by placing similar data entities on the same data file. Multiple data entities may be placed on a single data file when the structures of those entities are similar. A good example is data reference sets, which often have the same data attributes for code, name, definition, begin date, and end date. Rather than implementing a separate data file for each data entity, the data reference sets are placed on the same data file. A new data attribute is added to designate the specific data reference set, such as Data Reference Set. Identifier . The second exception could be resolved if the logical design planned ahead for putting multiple data reference sets on the same data file by adding Data Reference Set. Identifier to the logical data structure.