AMOUNT The two keys are NAME,DATE and ID,DATE. Note that NAME is dependent on ID, which is a proper subset of a key. However, NAME is a prime attribute since it is part of a key. Thus this is in third normal form, but not in Boyce Codd normal form. We create a file and specify that the pairs NAME,DATE and ID, DATE have unique values. Then the following violation of the dependencies could still take place on a data entry error.
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