* A clustered index : When only a single clustered index is present.
* A non-clustered index : When only a single non-clustered index is present.
* Many non-clustered indexes : When more than one non-clustered indexes is present.
* A clustered index and a non-clustered index : When a single clustered index and a single non-clustered index is present.
* A clustered index and many non-clustered indexes : When a single clustered index and more than one non-clustered indexes are present.
* No index : When there are no indexes present.
