Difference Between Clustered and Non-Clustered Indexes in SQL Server

Q

What Is the Difference Between Clustered and Non-Clustered Indexes in SQL Server?

✍: FYIcenter.com

A

SQL Server 2005 supports two types of indexes: clustered index and non-clustered index. Here are the main differences between them:

One table can only have only one clustered index.
One table can only have many non-clustered index.
A clustered index requires no separate storage than the table storage. It forces the rows to be stored sorted on the index key.
A non-clustered index requires separate storage than the table storage to store the index information.
A table with a clustered index is called clustered table. Its rows are stored in a B-Tree structure sorted.
A table without any clustered indexes is called non-clustered table. Its rows are stored in heap structure unsorted.
The default index created as part of the primary key column is a clustered index.

⇒ CREATE CLUSTERED INDEX - Adding Clustered Indexes in SQL Server

⇐ UNIQUE Constraint Creating Default Index in SQL Server

⇑ Understanding and Managing Indexes in SQL Server

⇑⇑ SQL Server Database Tutorials

2016-11-13, 2279🔥, 0💬

Creating a Large Table with Random Data for Indexes in SQL Server
How To Create a Large Table with Random Data for Index Testing in SQL Server? If you want to see how index can be used to improve data search performance, you have to build some large tables, which requires large amount of random data. This tutorial exercise helps you to build a large table with pur... 2016-11-13, 2890🔥, 0💬

sys.indexes - Viewing Existing Indexes on an Given Table in SQL Server
How To View Existing Indexes on an Given Table using sys.indexes in SQL Server? Another way to view existing indexes defined for a given table is to use the system view called "sys.indexes". The tutorial exercise shows you how many indexes were defined from the previous tutorial on table "fyi_links"... 2016-11-15, 2864🔥, 0💬

Index Slowing Down INSERT Statements in SQL Server
Does Index Slows Down INSERT Statements in SQL Server? If you want to see the impact of indexes on INSERT statements, you can repeat the same insert script on the table "fyi_links" of the same structure with two indexes: one non-clustered index on column "url" and one non-clustered index on column "... 2016-11-13, 2450🔥, 0💬

SP_HELP - Viewing Existing Indexes on an Given Table in SQL Server
How To View Existing Indexes on an Given Table using SP_HELP in SQL Server? If you want to know how many indexes have been defined for a given table, you can use the SP_HELP built-in stored procedure in the following syntax: EXEC SP_HELP table_name -- Returns all database objects related the given t... 2016-11-15, 2368🔥, 0💬

Difference Between Clustered and Non-Clustered Indexes in SQL Server
What Is the Difference Between Clustered and Non-Clustered Indexes in SQL Server? SQL Server 2005 supports two types of indexes: clustered index and non-clustered index. Here are the main differences between them: One table can only have only one clustered index. One table can only have many non-clu... 2016-11-13, 2280🔥, 0💬

CREATE CLUSTERED INDEX - Adding Clustered Indexes in SQL Server
How To Create a Clustered Index in SQL Server? If there is no primary key in a table, you can add one clustered index to that table with CREATE CLUSTERED INDEX statement. The tutorial exercise below shows you how to create a clustered index: USE FyiCenterData; GO -- Drop the old table, if needed DRO... 2016-11-13, 2231🔥, 0💬

UNIQUE Constraint Creating Default Index in SQL Server
Does the UNIQUE Constraint Create an Index in SQL Server? If you add the UNIQUE constraint on a column, SQL Server will automatically add a non-clustered index for that column. The tutorial exercise below shows you the index created as part of the UNIQUE column, "id", of "fyi_links": USE FyiCenterDa... 2016-11-13, 2203🔥, 0💬

Creating an Index for Multiple Columns in SQL Server
How To Create an Index for Multiple Columns in SQL Server? An index for multiple columns works similarly to a sorting process on multiple columns. If an index is defined for two columns, the index key is composed by values from those two columns. A multi-column index will be used to speed up the sea... 2016-11-13, 2186🔥, 0💬

Primary Key - Default Indexes of Tables in SQL Server
Is the PRIMARY KEY Column of a Table an Index in SQL Server? If you define a primary key on a table, an index for the primary key column will be created by default. The tutorial exercise below shows you the index created as part of the primary key column of "fyi_links": USE FyiCenterData; GO -- Drop... 2016-11-13, 2157🔥, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.