Normalization.
The process of evaluating and reorganizing table structure to reduce data redundancies is normalization. So, normalization is very important in database to perform task. In other words, normalization is also called Data Normalization.
What is data redundancies?
The repetition of data within a single database is data redundancies. And, to cope with data redundancy, Normalization and Master Data are used.
Advantages of Data redundancies.
As we know, there are following three advantages of Data redundancies.
- Excellent Data Security
- Alternative Data Backup.
- Faster Data Access.
Disadvantages of Data redundancies.
- Data inconsistency
- Increase in data corruption
- Increase in cost
Types Of Normalization.
There are various types of Normalization. But we are going to read about mainly 3 types of Normalization.
- 1NF
- 2NF
- 3NF
1. First Normal Form(1NF).
Each table should have single attribute while all the key attribute should be defined. Most importantly, each data in a table should be unique and dependent to primary key.
Example:
Random data
This table is not in 1NF form. In the subject of ram there is multi value attribute.
Conversion to 1NF
1NF
Now, the requirement of 1NF is fulfill.
2. Second Normal Form2NF
As we know 2NF is based on the concept of partial dependency. Moreover, partial dependency means non- key attributes are full dependent on Key attributes. So, to fulfill the requirement of 2NF table should be in 1NF and should not include the partial dependency.
Example:
Random data
The non key attribute is fully dependent in primary key attribute. So, the table are not in 2NF.
Conversion in 2NF:
Table 1
Table 2
Now, this table is in 2NF.
3. Third Normal Form3NF
It is based on transitive dependency. The value is functionally depend on non-key attribute is called transitive dependency. Therefore, if p=q, q=r and p=r, it is said to be a transitive dependency. In addition, to fulfill the requirement of 3NF, table should be in 2NF. And, it should not include the transitive dependency.
Example:
Random data
There is transitive dependency in table. Table is not in 3NF.
Conversion on 3NF:
Table 1
Table 2
Now this table fulfill the requirement of 3NF.
