Difference between 1NF and 2NF / Comparison of 1NF and 2NF / Compare 1NF and 2NF / 1NF and 2NF Comparison / 1NF and 2NF difference
Properties to be satisfied for 1NF and 2NF (recall)
1NF – All attribute values are atomic values, i.e,
no repeating group or no composite attributes present.
2NF – Table should be in 1NF and no partial
functional dependency presents.
Properties
|
1NF
|
2NF
|
Attribute
Domain
|
Should
be Atomic
|
Should
be Atomic
|
Functional
Dependencies Identification
|
Not necessary
|
Must
|
Handling
of Update Anomalies
|
Does
not handle. It deals with the basic structure of a relation.
|
Handle
update anomalies.
|
Composite
Key as Primary Key
|
Primary Key can be Composite
key
|
Primary Key cannot be
Composite key always. It may violate 2NF if partial key dependency exists.
That is, no partial functional dependency is permitted
|
Goal
|
Eliminate
Redundant Data
|
Ensure
Data Dependencies
|
*********
Related Links
- Go to Normal Form - Home page
- Go to Normalization - Home page
- Go to Normalization Solved Exercises - Home page
- Go to Comparison of All Normal Forms page