Second normal form

Second normal form (2NF) is a property of a relational model, specifically tables that is a criterion of database normalization. 
The first criterion of being second normal form is that the table be first normal form. 
Within a table that is in second normal form, the data in each columns in each row are dependent on each row's entire primary key. A primary key is one or more columns in a row that is used to identify and index that row of the table. Columns that are not related to every column in the primary key are removed. Only columns that are related to all columns in the primary key are retained.