By this stage, you should be familiar with the basics of SQL Server indexes. We've discussed what an Index actually is, as well as some of the most common types you're likely to encounter. Now that we've seen some simple examples of how Indexes can be useful, we're going to delve deeper into nonclustered indexes, as we'll see how they can improve the performance of more complex queries.
2021-05-12 (first published: 2014-11-26)
Included columns enable nonclustered indexes to become covering indexes for a variety of queries, improving the performance of those queries and with the only overhead being an increase the size of an index.
2019-03-27 (first published: 2011-07-13)
We've now seen how indexed and non-indexed tables perform in queries, and established "logical reads" as the metric for query performance. Now it is time to explain why logical reads are an excellent metric and also explain what is actually being read.
2019-03-06 (first published: 2019-01-16)
Indexes are the database objects that enable SQL Server to satisfy each data access request from a client application with the minimum amount of effort, resulting in the maximum performance of individual requests while also reducing the impact of one request upon another. Prerequisites: Familiarity with the following relational database concepts: Table, row, primary key, foreign key
2014-11-05 (first published: 2011-02-17)
Internal and external fragmentation – Causes, cures, and when not to care
2013-11-27 (first published: 2012-02-01)
Now that we've seen the basics of indexing, and taken a deeper dive into Nonclustered Indexes, this Level will focus on searching the table, which will, in turn, will lead us to a discussion of clustered indexes.
2013-01-25 (first published: 2011-06-22)