Quick overview 1NF-3NF
Data normalization exists in multiple levels, according to multiple rules. Normalization reduces data redundancy and increases data integrity. Informally, the cutoff for “well-normalized” is between 3NF and 4NF. Eventually, 6th Normal Form is what you’d call a whole host of Key-Value pairs, where the key is a Primary Key (this is known as a “Columnar data store”).
For well-Normalized data… put simply:
Every non-key attribute depends on the key (1st normal form) the whole key (2nd normal form) and nothing but the key (3rd normal form)
- Colorado State Paper
Unnormalized Data
- anything goes
First Normal Form (1NF)
- Cells contain only one value
Second Normal Form (2NF)
- Cells contain only one value
- All non-Prime fields are functionally dependent on the whole primary key
Third Normal Form (3NF)
- Cells contain only one value
- All non-Prime fields are functionally depending on the whole primary key
- All non-Prime fields are independent of each other
Source
Source
Relational Database Schema Design Overview