- MS Sql Server
- 822
- March-21-2018
- by Rizwan Saqib
NORMALIZATION
Database normalization,
Simply normalization, is the process of organizing the columns (attributes) and tables (relations) of a relational database to reduce data redundancyand improve data integrity. Normalization is also the process of simplifying the design of a database so that it achieves the optimal structure composed of atomic elements. It was first proposed by Edgar F. Codd, as an integral part of a relational model.
Features of Normalization
1.Normalization avoids the data redundancy.
2.It is a formal process of developing data structures.
3.It promotes the data integrity.
4.It ensures data dependencies make sense that means data is logically stored.
5.It eliminates the undesirable characteristics like Insertion Updation and Deletion Anomalies.
Reason Of Normalization
1. Redundancy Of Data
2. Insert Of data
3. Delete Of data
4. Update Of data
5. Waste of disk Space
Types of Normalization
Following are the types of Normalization:
1. First Normal Form
2. Second Normal Form
3. Third Normal Form
4. Fourth Normal Form
5. Fifth Normal Form
6. BCNF (Boyce – Code Normal Form)
7. DKNF (Domain Key Normal Form)
1.First Normal Form (1NF)
First normal form (1NF) is a property of a relation in a relational database.
A relation is in first normal form if and only if the domain of each attribute contains only atomic (indivisible)
values, and the value of each attribute contains only a single value from that domain.
2. Second Normal Form (2NF)
1.Conditions to make 2nd Normal form
1.Database Table must in First Normal form
2.All Non key attributes fully Functionally depends on key Attributes
2.What is key Attributes
Attributes having key is called key attribute
3.What is non key attributes
Attributes without any key is called non key attribute
3. Third Normal Form (3NF)
A table is in a third normal form when the following conditions are met −
1. It is must in second normal form.
2. All non Key Attributes An Fields are dependent on primary key.
3. No Transtive Dependence in Table
1.
We learn in 2nd Normal form Lecture in second
Normal form all non key attributes fully Functionally depend on Key attributes
2.
Transtive attribute means a non key Attribute depends on non key Attribute
Boyce-Codd Normal form (BC NF)
Define
Boyce-Codd Normal Form (BCNF) is one of the forms of database normalization. A database table is in BCNF if and only if there are no non-trivial functional dependencies of attributes
1.There are no non-trivial functional dependencies of attributes
