Clustered Index

If records are to be accessed sequentially and are placed at far places (different blocks) then the number of disk accesses increases resulting in inefficiency. Hence logically next records of a database should be placed on the same block to the extent possible i.e. “Records logically next should be physically close”. This storing of records in organizational way results in

1. Reduced number of disk accesses
2. On the page (block) we don’t need logical organization among records. They need not to be sorted.