What Are Indexes in SQL Server
What Are Indexes in SQL Server?
An index is a secondary database object associated with a table to improve the retrieval performance of rows from that table.
An index can be defined for a single column or multiple columns of a given table.
If an index is defined on a single column of a table, the index can be viewed
as ordered map between all values in that column and their row locations in the table.
For examples, if you have table with a column called "company_num"
and you created an index for that column. The contents of the table and the index
may look like what is presented in the following picture:
As shown in the above picture, locating the rows of company_num = 17 can be done much faster through the index.
2016-11-15, 1192👍, 0💬
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