A3.2.5 differences between normal forms

What is the focus of first normal form (1NF) ?

ensuring that all data is atomic and that each table has a unique identifier

What does second normal form (2NF) eliminate ?

partial-key dependencies by ensuring that all non-key attributes depending on the entire primary key

What is the key principle of third normal form (3NF) ?

removing transitive dependencies, ensuring that non-key attributes depend only on the primary key

What happens to repeating data in 1NF?

it is moved into a new entity

What is a common issue at the 1NF stage ?

partial key dependencies, where some attributes depend on only part of the composite keys

How are you parietal key dependencies handled in 2NF ?

they are removed into their own entity and a new primary key is assigned

What remains a problem after applying 2NF?

the presence of non-key (transitive) dependencies, attributes that do not rely on the key at all

What is the relationship between new primary key and foreign keys in 3NF?

the primary key becomes a foreign key in the entity it was removed from

What is the first step in achieving 1NF?

making the data atomic

What is th purpose of normalisation ?

to reduce the redundancy and ensures that all necessary data is stored in appropriate tables

How does 2NF resolve composite key dependencies?

by removing partial-key dependencies

What is the difference between data dependencies and composite key dependencies?

data dependencies are addressed by ensuring functional dependencies are properly managed, while composite key dependencies are resolved in 2NF by removing partial-key dependencies

What is the significance of eliminating transitive dependencies ?

it allows the structure to comply fully with the normalisation principle

What are the normalisation issues related to data duplication ?

normalisation reduces redundancy by eliminating duplicate data