what is indexes and type of indexes in sql server 2005?

Question

Kirtan Patel · Answer

Here Are Types of Indexes in the SQl Server 2005 if my answer helps you then check Do you like this answer checkbox please :) Index type Description Additional information Clustered A clustered index sorts and stores the data rows of the table or view in order based on the clustered index key. The clustered index is implemented as a B-tree index structure that supports fast retrieval of the rows based on their clustered index key values. Clustered Index Design Guidelines Clustered Index Structures Nonclustered A nonclustered index can be defined on a table or view with a clustered index or on a heap. Each index row in the nonclustered index contains the nonclustered key value and a row locator. This locator points to the data row in the clustered index or heap having the key value. The rows in the index are stored in the order of the index key values but the data rows are not guaranteed to be in any particular order unless a clustered index is created on the table. Nonclustered Index Design Guidelines Nonclustered Index Structures Unique A unique index ensures that the index key contains no duplicate values and therefore every row in the table or view is in some way unique. Both clustered and nonclustered indexes can be unique. Unique Index Design Guidelines Index with included columns A nonclustered index that is extended to include nonkey columns in addition to the key columns. Index with Included Columns Indexed views An index on a view materializes (executes) the view and the result set is permanently stored in a unique clustered index in the same way a table with a clustered index is stored. Nonclustered indexes on the view can be added after the clustered index is created. Designing Indexed Views Full-text A special type of token-based functional index that is built and maintained by the Microsoft Full-Text Engine for SQL Server. It provides efficient support for sophisticated word searches in character string data. Full-Text Index Population Spatial A spatial index provides the ability to perform certain operations more efficiently on spatial objects ( spatial data ) in a column of the geometry data type. The spatial index reduces the number of objects on which relatively costly spatial operations need to be applied. Spatial Indexing Overview Filtered An optimized nonclustered index especially suited to cover queries that select from a well-defined subset of data. It uses a filter predicate to index a portion of rows in the table. A well-designed filtered index can improve query performance reduce index maintenance costs and reduce index storage costs compared with full-table indexes. Filtered Index Design Guidelines XML A shredded and persisted representation of the XML binary large objects (BLOBs) in the xml data type column. Indexes on XML Data Type Columns

Gaurish Kumar · Answer

Hi An index is a physical structure containing pointers to the data. Indices are created in an existing table to locate rows more quickly and efficiently. It is possible to create an index on one or more columns of a table and each index is given a name. The users cannot see the indexes they are just used to speed up queries. Effective indexes are one of the best ways to improve performance in a database application. A table scan happens when there is no index available to help a query. In a table scan SQL Server examines every row in the table to satisfy the query results. Table scans are sometimes unavoidable but on large tables scans have a terrific impact on performance. Type of Indexes 1. Clustered indexes 2. Non-clustered indexes