Normalization
Dr. Edgar F. Codd proposes Normalization as an integral part of a relational model. Normalization is a database design technique which is used to organize the tables in such manner that ·it should reduce redundancy and dependency of data.
Normalization is a database design technique which is used to organize the tables in such manner that it should. reduce redundancy and dependency of data.
It divides larger rabies to smaller tables and links
these smaller tables using their relationships.
Normalization is implemented by following some formal rules either by a process of synthesis or decomposition. Synthesis is used to create database design in normalized form based on a known set of dependencies. Decomposition generally done on existing database which is not normalized. The relation of this database is further divided into multiple relations to improve the design.
- Normalization is the multi step process. It creates smaller tables from larger table.
Types of Normalization
1) First normal form (INF) : Having unique.
values, no repeating groups.
2) Second Normal form (2NF) Having unique values, no repeating groups, no partial dependency.
3) Third Normal form (3NF) : Same like second normal form and having transitive dependency.
4) Boyce-Codd Normal form (BCNF) : It is more developed ven,ion then 3NF.
S) Fourth normal form (4NF) : no multi-valued dependency.
3.5.1 Need of Normalization
- In database management process without Normalization, it is not easy to manage database operations like insertion, deletion, and modification without facing data l_oss problem.
If database is not normalized, then Insertion, Updation and Deletirn/--Anomalies occur frequently. To understand-need of normalization, first we should learn, what are Anomalies
3.5.1.1 Anomalies
Anomalies are inconvenient or error-prone situation arising when we process the tables. There are three types of anomalies :
A) Insert Anomaly
o An Insert Anomaly occurs when it is not possible to insert certain attributes into !he database without the availability of other attributes.
B) Update Anomaly
o An Update Anomaly occurs when there is requirement of changes in multiple records of an entity, but all records not get updated.
o For Example : Address of Kuna! get changed.
C) Delete Anomaly
o A Delete Anomaly is opposite to insert anomaly. This anomaly occurs when data of some attributes get lost because of deletion of data of other attributes in the same record.
o For Example : Just consider the only one entry for course Oracle of student Jay is deleted, then there will be no record related to course 'OS'. information of normlization
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