programming-for-dummies

384
Taking Action on Trees
Figure 5-10:
In a B-tree,
all leaf
nodes
appear at
the same
level.
In an ordinary tree, leaf nodes can appear
on different levels.
In a B-tree, all leaf nodes appear on the
same level.
When you add or subtract data, the binary tree constantly adjusts to keep all
leaf nodes at the same level. Keeping all leaf nodes at the same level ensures
that searching for some data (stored farther down a tree) won’t take a long
time compared to searching for other data (stored closer to the root node of
the tree).
A variation of a B-tree is a B+ tree. The main difference is that a B-tree can
store data in all its nodes. Because some nodes appear closer to the root
node than others, this makes searching for data closer to the root node fast
but searching for data farther from the root node slower in comparison.
A B+ tree only stores data in its leaf nodes and connects all leaf nodes
together as a linked list. Because all leaf nodes are the same distance from
the root node, this makes searching for any type of data equal.
Microsoft Windows and Linux are two operating systems that use B+ trees
for keeping track of files on a disk.
Taking Action on Trees
Trees are flexible data structures because they organize data and allow fast
retrieval of that data. Some of the different actions you can perform on trees
include
✦ Searching for a specific item
✦ Adding a new node or a sub-tree
✦ Deleting data or a sub-tree