It depends Michelle.
It depends what shop you are working at.
In some installations 3NF+ is the norm, in others....well no NF at all...the rest in between.
It is good practice to keep the database in 3NF.
Most violations result from "percieved performance" considerations (too many joins...) or rush job environment.
Performance can be addressed many ways, "denormalization" (actually unnormalization) is the worst way of addressing it.
Kalman Toth, Database, Data Warehouse and BI Architect
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