Avoid data duplicationIn an inventory database, vendor addresses should not
be stored with every part record. Otherwise, the address of a vendor who supplies 100 different parts will be repeated 100 times. Additionally, if the vendor’s
address changes, all 100 parts records must be updated. Data duplication also
can produce inconsistencies. If the 100 stored addresses for the vendor are not
identical, how would a user know which version is correct? In Chapter 9, you
will learn about data design and a technique called normalization, which is a set
of rules that can help you identify and avoid data design problems when you
create a database.