You may have heard the term Third Normal Form (3NF) when talking about databases and wondered what it meant. Quite simply, Normalization is a way to construct databases to standardize their appearance and to reduce duplication of data. Of the six normal forms (1st-5th and Boyce-Codd Normal Form or BCNF, another name for 3NF), 3NF is the most widely discussed, but First Normal Form (1NF) is the one we are most concerned with.
To be 1NF compliant, we need to eliminate duplicative columns from the same table, and create separate tables for each group of related data and identify each row with a unique column or set of columns (the Primary Key). In other words, we don't want to store duplicate data, we want to store it once and relate to it.
Essentially a 3NF database will store data in multiple tables to normalize the data and reduce duplication as we talked about earlier, and additionally: