An Introduction to Data Base Design by Betty Joan Salzberg (Auth.)

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.

Download PDF sample

Rated 4.45 of 5 – based on 10 votes