1. A clustered index is a special type of index that reorders the way records in the
table are physically stored. Therefore table can have only one clustered index. The
leaf nodes of a clustered index contain the data pages.
2. A non clustered 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. The leaf node of
a non clustered index does not consist of the data pages. Instead, the leaf nodes
contain index rows.