Index information is stored on index pages. An index page has the same layout as a data page. The difference is the type of information stored on the page. Generally, a row in an index page contains the index key and a pointer to the page or row at the next (lower) level.
The actual information stored in an index page depends on the index type and whether it is a leaf-level page. A leaf-level clustered index page is the data page itself; you’ve already seen its structure. The information stored on other index pages is as follows:
Clustered indexes, nonleaf pages—Each index row contains the index key and a pointer (the
fileId and a ...