Normalisation -database

Question

What is the difference between 2nf(second normal form and 3nf(third normal form).

Thank you

Answer 1

Database normalization is something that is hard to learn at first, but it is really easy.

In a very basic way it can be said that for a table to be in 2NF each column of a table must depend on the whole key and not constitute a unique data for each group of records. If a group of data is repeated for the same key, they must be separated into a new table.

The 3NF on the other hand tells us that no column can depend on a column that does not have a key and that there can be no derived data. That is, all fields that do not have a direct relationship with the key must be deleted.

That means that while 2NF reorganizes the structure of a database by grouping duplicate data in a table, 3NF removes all data that does not have a direct relationship with the key.