![DBMS Normalization](/wp-content/uploads/2022/11/DBMS-Normalization.png)
Normalization is a database schema design technique by which an existing schema is modified to minimize redundancy & dependency of data.
Normalization split a large table into smaller tables & defines relationships between them to increase the clarity in organizing data.
- Normalization is the process of organizing the data in the database.
- Normalization is used to minimize the redundancy from a relation or set of relations. It is also used to eliminate undesirable characteristics like Insertion, Update, and Deletion Anomalies.
- The normal form is used to reduce redundancy from the database table.
Data modification anomalies can be categorized into three types:
Insert Anomaly: Insertion Anomaly refers to when one cannot insert a new tuple into a relationship due to lack of data.
Delete Anomaly: The delete anomaly refers to the situation where the deletion of data results in the unintended loss of some other important data.
Update Anomaly: The update anomaly is when an update of a single data value requires multiple rows of data to be updated.
Types of Normal Forms:
Normalization works through a series of stages called Normal forms. The normal forms apply to individual relations. The relation is said to be in particular normal form if it satisfies constraints.
![](/wp-content/uploads/2022/11/NormalizationForm.png)
Following are the various types of Normal forms:
1NF | 2NF | 3NF | BCNF (Boyce-Codd Normal Form) | 4NF | 5NF |
---|---|---|---|---|---|
Eliminate Repeating Groups | Eliminate Partial Functional Dependency | Eliminate Transitive Dependency | Eliminate Overlapping Candidate Keys | Eliminate Multi-values dependency | Eliminate Join Dependency |
A relation is in 1NF if it contains an atomic value. | A relation will be in 2NF if it is in 1NF and all non-key attributes are fully functional dependent on the primary key. | A relation will be in 3NF if it is in 2NF and no transition dependency exists. | A stronger definition of 3NF is known as Boyce Codd’s normal form. | A relation will be in 4NF if it is in Boyce Codd’s normal form and has no multi-valued dependency. | A relation is in 5NF. If it is in 4NF and does not contain any join dependency, joining should be lossless. |
Advantages of Normalization
- Normalization helps to minimize data redundancy.
- Greater overall database organization.
- Data consistency within the database.
- Much more flexible database design.
- Enforces the concept of relational integrity.
Disadvantages of Normalization
#1NF #2NF #3NF #4NF #5NF #BCNF #database normalization #dbms #normalization
- You cannot start building the database before knowing what the user needs.
- The performance degrades when normalizing the relations to higher normal forms, i.e., 4NF, 5NF.
- It is very time-consuming and difficult to normalize relations of a higher degree.
- Careless decomposition may lead to a bad database design, leading to serious problems.