parentlevel

Parentlevel is a term used in data structures and software systems to denote the depth of a node's parent within a hierarchical structure. It is commonly defined as the level number of the parent node, equivalently the node's depth minus one. Depending on convention, the root level can be 0 or 1, and a node without a parent may have a null or undefined parentlevel.

In practice, parentlevel helps organize, render, and reason about nested data. It may be exposed as a field in relational queries or object models, and it can guide indentation, styling, or inheritance behavior in user interfaces and reports. If a system provides a dedicated level value for each node, parentlevel can be obtained by subtracting one from that value.

Implementation approaches vary. A node can carry an explicit level attribute that is updated on insert or move operations, or level can be computed during traversal by passing the parent’s level to children. In recursive queries, parentlevel can be derived from the parent’s level or by using a dedicated expression such as level minus one. Roots require special handling since they have no parent.

See also: depth; level; hierarchy; tree data structure; recursive query; adjacency list; nested set; closure table.