Database - What are indexes?

What are indexes?

- Index can be thought as index of the book that is used for fast retrieval of information.
- Index uses one or more column index keys and pointers to the record to locate record.
- Index is used to speed up query performance.
- Both exist as B-tree structure.
- Kind of the indexes are clustered and non-clustered.

Index is the way to order the records in a database according to the field values. It is the way to have fast access to the particular information. Indexes are created to the columns that are queried frequently.

What are the types of Indexes?

- Indexes can be clustered and non-clustered indexes.
- Clustered index keeps all the records in the database in the order of clustered index key.
- There can be only one clustered index per table.
- Non-clustered indexes are stored as B-tree structure in their own storage separate from data storage in the table

What are the disadvantages of the Indexes?

- Indexes improve query performance but it slows down data modification operations.
- Indexes consume disk space.

What are indexes?

An index of a data base is a data object or structure which is utilized for improving the operations speed in a specific table. Index is a subset of columns from a table. The values in a subset are stored in a sorted order and the database server can quickly finds the records which are based on the data in the index.