Simple understanding of database three paradigms

Three paradigms of database

1. First normal form: All attributes in an entity are the most basic data units that cannot be decomposed, ensuring the atomicity of each column.

2. Second normal form: Based on the first normal form, all non-primary attributes are completely dependent on the primary key.

3. Third normal form: Based on the second normal form, attributes in an entity cannot be non-primary attributes of other entities. (Each column of data is directly related to the primary key and cannot be indirectly related)