What is Normalization in SQL Server database?
What is Normalization in SQL Server database?
27510-Nov-2021
Updated on 10-Nov-2021
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What is Normalization in SQL Server database?
Steilla Mitchel
11-Nov-2021Database Normalization:
Normalization is the process of organizing data. Generally it is a two step process which is as follows:-
Step-1: In the first step, it eliminates the redundant data (the data which is stored more than once) from the relational table.
Step-2: In the second step, it ensures that only the data related to it is stored in the table.
The main purpose of normalization is to create a set of relational tables that do not contain redundant data and can be modified continuously and accurately.
Types of Normal form:
There are several types of normal form in SQL Server as like-
First normal form (1NF): A table is in first normal form when it does not contain repeating groups (the same data repeatedly).
The relation or table that keeps repeating groups is called Un-normalized relation or table.
Second normal form (2NF): A table or relation is in 2nd normal form when it satisfies all the requirements of 1st normal form and all non key attributes are completely dependent on primary key.
Third normal form (3NF): A table or relation is in 3rd normal form when it satisfies all the requirements of 2nd normal form and should not have transitive function dependency.
Transitive functional dependency means if X is functionally dependent on Y and Y is functionally dependent on Z then Z will be transitively dependent on X and Y.
Fourth normal form (4NF): A relation or table is in 4NF when it satisfies the following condition,
'A relation or table is in 4NF if it is in third normal form (3NF) and has no multivalued dependencies.'
Fifth normal form (5NF): A relation or table is in 5NF when it satisfies the following condition:-
“A table or relation is in 5NF when it is in 4NF and there is no non-loss decomposition in the table.”
Boyce Codd Normal Form:
The Boyce Codd normal form is the higher version of 3NF, sometimes referred to as 3.5NF.
That table or relation which is in 3NF is also in BCNF but there is a special condition for BCNF which is as follows:-
A table or relation is then in BCNF if each of the determinants is a super key.