Normal Forms: A Recap
The key, the whole key, and nothing but the key, so help me Codd.
The key stands for 1NF: all tables must have a (primary) key because all records in the table must be unique.
The whole key stands for 2NF: no functional dependencies on part of the key are allowed.
Nothing but the key (attribute) stands for 3NF: no functional dependencies between non-key attributes are allowed.
Nothing but the key stands for BCNF: only functional dependencies out of candidate keys are allowed.
“2NF/3NF: Every non-key attribute is
dependent on the key, the whole key, and nothing but the key—so help me Codd.”
The db from…
Database diagram used for some learning (Bikestore)
The rest is here: