RE: normalization

It violates 3NF.

But the argument is moot. The correct question to ask is:

"Will the simplification and speed increases gained by storing the calculated result more than offset the increases in complexity to keep the calculation and the source fields synchronized plus the risk that you don't properly synchronize them?"

FWIW, the referenced document uses the classically wrong example of:

> <http://www.alphabetcitydataworks.com/FundamentalsOfRelationalDatabaseDesign.doc>

data items = quantity sold and unit price calculated value = line total price

The correct example is:

data items = quantity sold and line total price calculated value = unit price

Try recording "3 for a dollar" using the first example...

Otherwise, the document looked quite good at a quick glance.

--
http://www.freelists.org/webpage/oracle-l