1.Clustered Index - A file is organized so that the ordering of the data records is the same as or close to the ordering of data entries in some index.Than that index is called Clustered Index. Ex. Age.
That is non key and ordered on some column..
2.Unclustred Index - is a special type of index in which the logical order of the index does not match the physical stored order of the rows on disk.
3.Dense Ondex - In dense index, there is an index record for every search key value in the database. Index records contain search key value and a pointer to the actual record on the disk.
4 Sparse Index - In sparse index, index records are not created for every search key rather than for some search keys.That's why it is called sparse.
