Third Normal Form

According to second normal form table should be in Second Normal Form and we should have to remove Transitive Functional Dependency.

In the above Emp-Info table non-key column DName dependent part on the other non-key column that is DeptNo. It means there existed Transitive functional dependency.

To make the table into third normal form we have to divide the table into multiple tables.

Proj-Info:

ProjNo:p1
Pname:pn1
Bud:--

Emp-Info:

EmpNo:11
Ename:------
sal:------


Dept-Info:

DeptNo:10
DName:----
Loc:------

Third Normal Form

Second Normal Form

According to second normal form table should be in First Normal form and we should have to remove Partial Functional Dependency.

In the above table DeptNo non-key column dependent part of the Primary Key column that is EmpNo.It means there existed Partial functional dependency.

To make the table into second normal form we have to divide the table into multiple tables.

Proj-Info:

ProjNo:p1
Pname:Pn1
Bud:----

Emp-Info:

EmpNo:11
EName:----
Sal:-------
DeptNo:-----
DeptName:-----
Loc:-----

Second Normal Form

First Normal Form

According to first normal form table should contain only single values columns.But in the above mentioned un-normalized table see this:http://sqlserver-guide.blogspot.com/2009/04/normalization.html
the columns ProjNo and PName contain multiple values.

To make the table into first normal form we should have to split the multiple values into single values

EmpNo:11
ProjNo:p1
EName:----
PName:Pn1
Sal:----
Bud:-----
DeptNo:10
DName:--------
Loc:------

First Normal Form

Normalization

Normalization is process of splitting the base table into multiple tables based on the theory of Functional Dependency.

Or

Normalization is repetitive process in order to identify the functional dependencies among the columns and to remove them. If any functional dependency is occurred after the normalization process again we have to start the same process until all functional dependencies have been removed.

To do this Normalization we have to follow rules or conditions called Normal Forms.

Un-Normalized Table:

EmpNo=11
ProjNo=p1,p2
EName=-----
PName=Pn1,Pn2
Sal =-----
Bud=------
DeptNo=10
Dname=------
Loc=------

EmpNo and ProjNo are Primary keys called 'COMPOSITE PRIMARY KEY'

Normalization