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
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.
Internal and external fragmentation – Causes, cures, and when not to care
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.
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.
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Trunk based development is what many of us do with shared database servers.
When you index a nullable field, are the rows with nulls stored in the index? It’s easy enough to find out by creating a table with a nullable field, and then creating an index on it.
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A table without a clustered index (heap) will NOT suffer from fragmentation during frequent updates or deletes. True or False?
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