What Is Difference Between Cluster Index And Non Cluster Index?

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3 Answers

ayesha sana Profile
ayesha sana answered
Indexes are used in databases and they are used to create tables. Each is used to create independent data. This approach is basically used in SQL Server 2000 database.
The major differences between the cluster and non cluster indexes are as follows.

Cluster Index

1 A cluster index is a form of tables which consist of column and rows.
2 Cluster index exists on the physical level
3 It sorts the data at physical level
4 It works for the complete table
5 There is a whole table in form of sorted data
6 A table can contain only one cluster index

Non Cluster Index

1 A non cluster index is in the form of a report about the tables.
2 They are not created on the physical level but at the logical level
3 It does not sort the data at physical level
4 A table has 255 non clustered indexes
5 A table has many non clustered indexes.
6 It work on the order of data

The table can have indexes in many forms. A table cannot have a single index in it, neither cluster and nor non cluster index. It is also possible that a table has only single cluster index and does not have any non clustered index or vice versa.
Daisy Sarma Profile
Daisy Sarma answered
Indexes are used to sort data in a table. There are two basic types of indexes – clustered and non clustered. Both of these are used in SQL. While both serve the same purpose of indexing data, there are basic differences in the way they perform their roles. A clustered index sorts the data in a table physically. A non clustered index does not sort the data physically. Another difference between the two is in the structure of the leaf layer. While you can have just a single clustered index per table, it is possible to have multiple non clustered indexes in a single table, with a maximum of 255 such indexes per table a very authentic possibility. What this means essentially is that for every single column in a table, you can utilize one non clustered index.

Besides these, there are also differences in the scenarios when you can use a clustered or a non clustered index. The former is a safe bet if you are working with a table having a large number of unique data, such as a table containing the employee IDs for the different members of an organization. These IDs are always unique, and using a clustered index is a good way of retrieving this large volume of unique data rapidly. On the other hand, a non clustered index is the best approach if you have a table that does not contain too many such unique values. These are just some of the differences between the two. You can read in detail about these differences by putting a search on the Internet for the differences between the two.
Janjua Ibrahim Profile
Janjua Ibrahim answered
This is a enormous question. A single clustered index can be created on a table and this index physically sorts the data for the entire table based on the values in this column. A table can have up to 255 non clustered indexes. Non clustered indexes are based on order of the data, but do not physically sort the data.
A table can have one of the following index configurations:
• No indexes
• A clustered index
• A clustered index and many non clustered indexes
• A non clustered index
• Many non clustered indexes

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