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Explain Normalization in Details


Posted Date: 15 Jul 2011      Posted By:: priyanka sharma     Member Level: Bronze    Member Rank: 3794     Points: 1   Responses: 8



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




Responses

#620556    Author: Ganeshgoud      Member Level: Silver      Member Rank: 995     Date: 15/Jul/2011   Rating: 2 out of 52 out of 5     Points: 2

Hi,

Normalization is the process of eliminating the DataRedendency

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

Thanks
Ganeshgoud


 
#620558    Author: Prabu Thangavelu      Member Level: Gold      Member Rank: 83     Date: 15/Jul/2011   Rating: 2 out of 52 out of 5     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.

Prabu Thangavelu


 
#620564    Author: Suresh      Member Level: Gold      Member Rank: 156     Date: 15/Jul/2011   Rating: 2 out of 52 out of 5     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

"IF YOU WANT TO SHINE LIKE A SUN FIRST YOU HAVE BURN LIKE IT".





 
#620566    Author: Anjali      Member Level: Silver      Member Rank: 1298     Date: 15/Jul/2011   Rating: 2 out of 52 out of 5     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


 
#620570    Author: vishal      Member Level: Bronze      Member Rank: 2407     Date: 15/Jul/2011   Rating: 2 out of 52 out of 5     Points: 1

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


 
#620575    Author: kirthiga      Member Level: Gold      Member Rank: 456     Date: 15/Jul/2011   Rating: 2 out of 52 out of 5     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


 
#620585    Author: keerthi      Member Level: Silver      Member Rank: 895     Date: 15/Jul/2011   Rating: 2 out of 52 out of 5     Points: -1

[Response removed by Admin for invalid response to the thread or violation of forum policies.]

 
#620647    Author: Paritosh Mohapatra      Member Level: Gold      Member Rank: 9     Date: 15/Jul/2011   Rating: 2 out of 52 out of 5     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.


Thanks & Regards
Paritosh Mohapatra
Microsoft MVP (ASP.Net/IIS)
DotNetSpider MVM


 
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