Microsoft® SQL Server 2008 R2 Unleashed

Essential Denormalization Techniques

You can use various methods to denormalize a database table and achieve desired performance goals. Some of the useful techniques used for denormalization include the following:

• Keeping redundant data and summary data

• Using virtual columns

• Performing horizontal data partitioning

• Performing vertical data partitioning

Redundant Data

From an I/O standpoint, joins in a relational database are inherently expensive. To avoid common joins, you can add redundancy to a table by keeping exact copies of the data in multiple tables. The following example demonstrates this point. This example shows a three-table join to get the title of a book and the primary author’s name:

You could improve the performance of ...