Table Access (UPDATE) Using B* Tree
Table Access Using B* Tree
is illustrated using the example of an UPDATE statement.
If an UPDATE is performed and the
primary key
remains unchanged, only the contents of the table row are changed.
If the data length changes, the positions of subsequent entries and their addresses in the position list of the
leaf page
in the
B* tree
are changed.
If the key field changes, the UPDATE is executed as a DELETE (
Table Access (DELETE) Using B* Tree
) with a subsequent INSERT (
Table Access (INSERT) Using B* Tree
).