- Clustered indexes can randomize data inserts, avoiding insert “hot spots” on the last page of a table.
- Indexes can help avoid sorts, if the index order matches the order of columns in an order by clause.
In addition to their performance benefits, indexes can enforce the uniqueness of data.
A table that has no clustered index is called a heap. The rows in the table are in no particular order, and all new rows are added to the end of the table.
