Question

Explain ...1-NF, 2-NF, 3-NF and BCNF​

Answer 1

Explanation:

Database normalization is a database schema design technique, by which an existing schema is modified to minimize redundancy and dependency of data.

1NF-Each column is unique in 1NF.

2-NF-The entity should be considered already in 1NF, and all attributes within the entity should depend solely on the unique identifier of the entity.

3-NF-The entity should be considered already in 2NF, and no column entry should be dependent on any other entry (value) other than the key for the table.

If such an entity exists, move it outside into a new table.

3NF is achieved considered as the database is normalized.

BCNF-3NF and all tables in the database should be only one primary key.