Creating Indexes to Provide Faster Query Execution
Now we will have a look at how indexes work and how they improve query performance. In SQL Server, it is possible to define two different types of indexes: clustered indexes and nonclustered indexes. To understand how indexes can improve data access and which index type to use for a given situation, it is essential to understand how data and indexes are stored in data files and how SQL Server accesses data in data files.
A data file in a SQL Server database is divided in 8k pages. Every page can contain data, indexes, or other types of data that SQL Server needs to maintain the data files. However, the majority of the pages are data or index pages. Pages are the units that SQL ...