All SAP DB data is stored in structures called B* trees. The B* tree method is far more efficient for accessing the rows of a table than other access methods (for example, sequential scans).
A B* tree spans several levels from the root level at the top, to the index levels, through to the lowest leaf level (one root level, n index levels (n>=1), one leaf level).
The storage units are called pages or data pages. SAP DB Version 7 supports a page size of 8 KB.
In SAP DB Version 7, all subsequent comparisons in a B* tree use ASCII code (each character is assigned a numerical value between 0 and 255). The comparisons are performed for all values on a character-by-character basis.
The sort criterion for building a B* tree is the
primary key.B* Tree
See also:
Root/Index Page Leaf Page Table Access B* Trees for Tables