ARCHIVE / What is a data tree?
A data tree is a form of data structure that follows one simple rule. No node may reference another node that itself references the originating node either directly or indirectly. A stricter version also includes a second rule. No node may be referenced by more than one other node. Because of the similarity to a family tree, data trees often use familial terminology, such as "parent", "ancestor", "sibling" and "child". However, because family trees require two parents to have a single child, family trees cannot be considered strict data trees. As such, strict data trees are more like actual trees in that multiple branches rarely merge to become a single branch. When drawn, data trees are conventionally shown with the originating node at the top. This allows people to effectively read the data tree from top to bottom, as people are accustomed to from reading in almost all written languages.
Note that the red lines with the black marks are forbidden for strict data trees with only the reference from H to A forbidden in non-strict cases.
last updated 2008.02.19
What is a data structure?