What is denormalization?

What is denormalization?

- Denormalization is the reverse process of normalization.

- It is controlled introduction of redundancy to the database design.

- Database design is denormalised to improve the query performance.

- It is done to reduce the number of complex joins in the query.

- Denormalization 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.

- This is done to speed up database access by moving from higher to lower form of normalization.
How do you implement one-to-one in SQL Server?
One to one is implemented using single table by establishing relationship......
How do you implement one-to-many in SQL Server?<
Implemented using two tables with primary key and foreign key relationships......
How do you implement many-to-many SQL Server?
Implemented using a junction table. The keys from both the tables form composite primary key of the junction table......
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Denormalization in sql server
Very informative post. Its really helpful for me and beginner too. Check out this link too its also having a nice post related to this post over the internet which also explained very well...
http://mindstick.com/Articles/2168d768-017c-41f4-a7a3-ac76faabb48d/?Denormalization%20in%20SQL%20Server

Thanks
Rumesh Singh 12-27-2011