Database - Database Design Using Normalization - Discussion

Normalization basically reduces redundancy, and may eliminate duplicates. But generally, it reduces. So, the Answer should be B reduces.

The answer is B reduces.

Why do we say reduce data duplication rather than eliminate data duplication? The answer is that we cannot eliminate all duplicated data. Because we must duplicate data in foreign keys. We cannot eliminate Buyer.

For example: From the SKU_DATA table, because we would then not be able to relate BUYER and SKU_DATA rows. Values of Buyer are thus duplicated in the BUYER and SKU_DATA tables.

This observation leads to a second question If we only reduce data duplication. How can we claim to eliminate inconsistent data values? Data duplication in foreign keys will not cause inconsistencies, because referential integrity constraints prohibit them.

As long as we enforce such constraints, the duplicate foreign key values will cause no inconsistencies.

I am agree with you, it reduces not eliminates, it also depends which normal form we are using.

Normalization reduces duplication of data, but not eleminate it completly.