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Explain Normalization in Details

plz tell me about normalization.
what is the type of that?
what is the deiffrence detween that?


Comments

Author: Ganeshgoud15 Jul 2011 Member Level: Silver   Points : 2

Hi,

Normalization is the process of eliminating the DataRedendency

simply making well structured database.without partial dependency
and functional dependency.

Author: Prabu Thangavelu15 Jul 2011 Member Level: Gold   Points : 4

Hi Priyanka,

Normalisation is a process which is used to organising database in a well structured manner and avoid redundancy of data, i.e., repeating data again and again with giving relationships between data.

I guess 6 Normal Forms are available. But i know only 3.

First Normal Form : Enforces unique data that means avoid repeating data or duplicate values.
We can solve this problem using creating of primary key.

Second Normal Form : All other attributes should depend on the primary key.

Third Normal Form : Avoid repeating data that means if we having huge table with no of columns, here we can separate that table into some more simple tables and give relationships to them.

Author: Suresh15 Jul 2011 Member Level: Gold   Points : 2

Hi,

Normalization is Set rules for creating Database.It is Used To avoid repetitive entries, increase performance.

First Normal Form
Third Normal Form
Second Normal Form

Thanks
S.Suresh

Author: Anjali15 Jul 2011 Member Level: Silver   Points : 4

There are 4 normal forms namely..

First Normal Form:

In this Normal Form all values should be atomic. Set Primary key for not allowing duplicate column.


Second Normal Form:

With this normal form Foreign key concept is used. It wont allows for Duplicate row.

Third Normal Form:

We can reduce the column for aggregate function such as total,age calculation grade calculation. We no need to specify separate column instead we can assign that column in select query or in code behind itself.


Boyce Code Normal Form

Author: vishal15 Jul 2011 Member Level: Bronze   Points : 1

normalization is used to remove data redundancy.
De-normalization is reverse process.

Author: kirthiga15 Jul 2011 Member Level: Gold   Points : 4

Normalization:
Normalization is the process of organizing data.
To establish relationships between tables
To make the database more flexible by eliminating redundancy and inconsistent dependency.

Consider this table:


Student Faculty Faculty_No Stud1 Stud2 Stud3
Ram Latha 101 1001 1021 1041
Kamal Priya 102 1061 1071 1091


First Normal Form:
Eliminate repeating groups in individual tables.
Create a separate table for each set of related data.
Identify each set of related data with a primary key.


Student Faculty Faculty_No Stud1
Ram Latha 101 1001
Ram Latha 101 1021
Ram Latha 101 1041
Kamal Priya 102 1061
Kamal Priya 102 1071
Kamal Priya 102 1091


Second Normal Form:
Create separate tables for sets of values that apply to multiple records.
Relate these tables with a foreign key.


Student Faculty Faculty_No
Ram Latha 101
Kamal Priya 102



Student Stud1
Ram 1001
Ram 1021
Ram 1041
Kamal 1061
Kamal 1071
Kamal 1091


Third Normal Form:
Eliminate fields that do not depend on the key.


Student Faculty
Ram Latha
Kamal Priya



Faculty Faculty_No
Latha 101
Priya 102

Author: keerthi15 Jul 2011 Member Level: Silver   Points : -1

Hi,

Normalization is used remove redundant data.
These are the forms of Normalization.


1NF: Eliminate Repeating Groups
Make a separate table for each set of related attributes, and give each table a primary key. Each field contains at most one value from its attribute domain.
2NF: Eliminate Redundant Data
If an attribute depends on only part of a multi-valued key, remove it to a separate table.
3NF: Eliminate Columns Not Dependent On Key
If attributes do not contribute to a description of the key, remove them to a separate table. All attributes must be directly dependent on the primary key
BCNF: Boyce-Codd Normal Form
If there are non-trivial dependencies between candidate key attributes, separate them out into distinct tables.
4NF: Isolate Independent Multiple Relationships
No table may contain two or more 1:n or n:m relationships that are not directly related.
5NF: Isolate Semantically Related Multiple Relationships
There may be practical constrains on information that justify separating logically related many-to-many relationships.

Author: Paritosh Mohapatra15 Jul 2011 Member Level: Gold   Points : 4

Normalization is a scientific method of breaking down complex table structures into simple table structure by using certain rules.

Benefits of normalization of the database includes:

1) Avoiding repetitive entries.
2) Reducing required storage space.
3) Preventing the need to restructure existing tables to accommodate new data.
4) Increased speed and flexibility of queries, sorts and summaries.

First Normal Form
-----------------

A relation is said to be in First Normal Form (1NF) if the values in the domain of each attribute of the relation are atomic. In other words, only one value is associated with each attribute and the value is not a set of values or a list of values.

Second Normal Form
------------------

A relation R is in second normal form (2NF) if it is in the 1NF and if all non-key attributes of R are fully functionally dependent on the primary key of R.

Third Normal Form
-----------------

A relation R is in third normal form (3NF) if and only if it is in 2NF and no non-key attribute of R is transitively dependent on the primary key of R.

Boyce-Codd Normal Form
----------------------

A relation R is in Boyce-Codd Normal Form (BCNF) if and only if every determinant is a candidate key.