Learn Database Normalization - 1NF, 2NF, 3NF, 4NF, 5NF
Watch this video to get a comprehensive breakdown of database normalization from First Normal Form (1NF) to Fifth Normal Form (5NF):
Summary
In database normalization, each "normal form" sets out specific criteria that build upon each other to guide how tables should be structured. Here’s the breakdown as presented in the video:
Using row order to convey information is not permitted. Mixing data types within the same column is not permitted. Having a table without a primary key is not permitted. Repeating groups are not permitted. Second Normal Form (2NF): Each non-key attribute in the table must be dependent on the entire primary key. Each non-key attribute in a table must depend on the key, the whole key, and nothing but the key. If we drop the phrase "non-key," we arrive at an even stronger version of Third Normal Form known as Boyce-Codd Normal Form (BCNF):
Every attribute in a table should depend on the key, the whole key, and nothing but the key. Fourth Normal Form (4NF): The only kinds of multivalued dependency we’re allowed to have in a table are multivalued dependencies on the key. It must not be possible to describe the table as being the logical result of joining some other tables together. These forms act as guiding principles in designing the schema of your tables, ensuring they are fully normalized to reduce redundancy and maintain data
