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What is Denormalization?

What is Denormalization?.

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What is Denormalization?

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  1. What is Denormalization? • Sometimes it is appropriate for a designer to purposely denormalize parts of a database. A database designer must do this with forethought in order to a negative impact to performance and ease of use. By denormalizing the design, less join tables and foreign keys are required. Denormalization can be used on First and Second Normal Form; however, it should never be used on Third Normal Form.

  2. Normalization 1. Normalization Normalization is technique in which we reformat and design database and break in in such way that it can give us more speed and integrity constraints and restriction of business rules. 120 70 2. De-normalization Database is transferred from Normalized to De-normalized to create data ware house. 50 30 Data Warehouse 2003 2004 2005 2006

  3. Denormalization can improve performance by: • Minimizing the need for joins • Precomputing aggregate values, that is, computing them at data modification time, rather than at select time • Reducing the number of tables, in some case • . Denormalization improves the database performance in many ways. It cuts down on the need for joins. Denormalization also improves reading data because it is readily available.

  4. What is the difference between Normalization and Denormalization ? • Normalization and denormalization are two processes that are completely opposite. • Normalization is the process of dividing larger tables in to smaller ones reducing the redundant data, while denormalization is the process of adding redundant data to optimize performance. • Normalization is carried out to prevent databases anomalies. • Denormalization is usually carried out to improve the read performance of the database, but due to the additional constraints used for denormalization, writes (i.e. insert, update and delete operations) can become slower. Therefore, a denormalized database can offer worse write performance than a normalized database. • - It is often recommended that you should “normalize until it hurts, denormalize until it works”. • Normalizing data means eliminating redundant information from a table and organizing the data so that future changes to the table are easier.

  5. What is denormalization and when would you go for it? Denormalization or Normalization both we use on databse so that any one can filter as well as retrive the data from the tabel easily.Denormalization - As the name suggest it is a reverse process of normalization, means we fill some redundant data in table so that user can retrive easily.But actualy we use the major functionality of normalization of higher normal form(BCNF, 4TH NF ,5TH NF, DKNF) in lower normal form (1st and 2nd) because higher normal forms are so costly to use, thats why we use denormalization to 

  6. THE END

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