Normalization and Denormalization

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Normalization
Steps of normalization
De-normalization

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Define Normalization and De- Normalization.

By Nishant Kumar

Normalization

  • It is the process of organizing data into related table.
  • To normalize database, we divide database into tables and establish relationships between the tables.
  • It reduces redundancy. It is done to improve performance of query.

Steps of normalization:

First Normal form
Entities of the table must have unique identifier or entity key.
Second Normal Form
All the attributes of the table must depend on the entity key for that entity.
Third Normal Form
All attributes that are not part of the key must not depend on any other non-key attributes.

De-normalization

The process of adding redundant data to get rid of complex join, in order to optimize database performance. This is done to speed up database access by moving from higher to lower form of normalization.

Sql server - Define Normalization and De- Normalization - Feb 11, 2010 at 11:55 AM by Shuchi Gauri

Define Normalization and De- Normalization.

Normalization is the process of reducing data redundancy and maintains data integrity. This is performed by creating relationships among tables through primary and foreign keys. Normalization procedure includes 1NF, 2NF, 3NF, BCNF, and then the data is normalized.

Denomalization on the contrary is the process of adding redundant data to speed up complex queries involving multiple table JOINS. One might just go to a lower form of Normalization to achieve Denormalization and better performance. Data is included in one table from another in order to eliminate the second table which reduces the number of JOINS in a query and thus achieves performance.

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