Database Reference
In-Depth Information
Let's assume that you want to create a clustered index on the heap table with the data. At a first step, which is
shown in Figure
2-5
, SQL Server creates another copy of the data that is sorted based on the value of the clustered key.
The data pages are linked in a double-linked list where every page contains pointers to the next and previous pages in
the chain. This list is called the
leaf level
of the index, and it contains the actual table data.
Figure 2-5.
Clustered index structure: Leaf level
■
Note
the sort order on the page is controlled by a slot array. actual data on the page is unsorted.
When the leaf level consists of the multiple pages, SQL Server starts to build an
intermediate level
of the index,
as shown in Figure
2-6
.
Figure 2-6.
Clustered index structure: Intermediate and root levels
