When you delete a row from an allpages-locked table that has a clustered index, other rows on the page move up to fill the empty space so that the data remains contiguous on the page.
Figure 9-5 shows a page that has four rows before a delete operation removes the second row on the page. The two rows that follow the deleted row are moved up.
Figure 9-5: Deleting a row from a table with a clustered index
