Difference between cluster and non-clustered index in SQL

Question

Just to know the question of the interview and my knowledge.

Difference between Cluster and Non-cluster index ?

Answer 1

Link describing two.

http://www.mssqlcity.com/FAQ/General/clustered_vs_nonclustered_indexes.htm

http://www.sql-server-performance.com/articles/per/index_data_structures_p1.aspx

The difference lies in the physical order of the entries in the table relative to the index. The clustered index is physically ordered in this way in the table.

Answer 2

Cluster Index

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

Non-cluster index

1 The non-clustered index is in the form of a table report.
2 They are not created at the physical level, but at the logical level
3 It does not sort data at the physical level
4 The table has 255 non-clustered indexes
5 There are many non-group indexes in the table.
6 He works on data order

Answer 3

Clustered index

• For table only
• Faster to read than non-clustered because data is physically stored in the index

Nonclustered Index

• Can be used many times for a table.
• Faster for insert and update operations than clustered index

Both types of indexes improve performance when selecting data with fields that use the index, but slow down the update and insert operations.

the difference is that a clustered index is unique to any given table, and we can only have one clustered index in a table. The leaf level of the clustered index is the actual data, and the data is applied to the clustered index. If in a non-clustered index , the sheet level is actually a pointer to the data in the rows, so we can have as many non-clustered indexes in the database as possible.

Answer 4

The difference between the cluster index and the noncluster index:

• The cluster index has only one column in the table and is slow when inserting, updating, and searching, one for each column.
• An index without a cluster its process is faster than when they are inserted or updated, and it searches only the identifier not for each column of the table.