Asked By
ElbertJam
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Posted on - 08/27/2011
Hi,
What is normalization? and what is de-normalization?
Explain different levels of normalization.
Can anyone help me understand this?
Regards
Answered By
rojonn
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N/A
#119473
What is normalization? and what is de-normalization?
Normalization is a basic method for database management system. Normalization is best for data formation of Database. It is one of the greatest data formations of Database. It has 6 normal form but 4 of them are basic.
1.      The first normal form holds very basic rule for Normalization
2.      The next one is basically used for redundancy remove from database.
3.      It controls the 2nd form so it contains parameter of 2nd.
4.      This one known for code of normalization.
These are the basic Normalization forms.
De-normalization is also important for database management system. It is a process for optimize the database performance.
What is normalization? and what is de-normalization?
Normalization is to minimize redundancy of data and provide data integrity. There are six normal forms we go through during normalization process.
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First Normal Form (1NF) – Eliminate duplicate columns in the table. Group related data by tables and set a primary key for each table.
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Second Normal Form (2NF) – Must meet 1NF. And create relationships to related tables through the use of foreign keys.
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Third Normal Form (3NF) – Must meet 2NF. Check if there are columns in the table not dependent to the primary key. Transfer to another related table or create one.
Boyce-Codd Normal Form – A heavy implementation of 3NF.
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Fourth Normal Form (4NF) – Must meet 3NF or BCNF. Deals with many to many and many one relationships. There should be no two or more independent multi-valued fields in the table. They should be separated into another table.Â
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Fifth Normal Form (5NF) – Stresses to maintain lesser redundancy of data, other things not covered by the previous NFs.As you go along normalization process, more tables are added and thus more join queries you have to make.
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This would now create negative impact on performance and so you would need redundant data to optimize back performance. This is what is called de-normalization.
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Therefore we can conclude, normalization is needed but not absolute.
What is normalization? and what is de-normalization?
Normalization helps you to manage your database in a structured way. This procedure includes 4 levels to finish the process. We have
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1st normal form which covers the removal of unnecessary information in the database,
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2nd normal form that can be done when you set foreign keys for the relationship of the tables,
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3rd normal form which covers the deletion of information that are not relying on the primary key of the table and lastly the
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4th normal form which combines the other 3 levels.
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Take note that for every level before you can continue, the lower level is the prerequisite of the next level.
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On the other hand we also have a procedure called De-normalization which includes unnecessary information in the table to manage the database’s relationship.
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