The '''nested set model''' is a particular technique for representing [[nested set]]s (also known as [[tree (data structure)|tree]]s or [[hierarchy|hierarchies]]) in [[relational database]]s.
The term was apparently{{clarify|date=October 2018}} introduced by [[Joe Celko]]; others describe the same technique using different terms.<ref>[http://www.infokarta.com/content/relational-taboo-recursive-dimensions-and-topological-ordering-nested-sets Recursive Dimension Hierarchies: The Relational Taboo by Michael Kamfonas originally published at the Relational Journal in 1992]</ref><ref>[http://articles.sitepoint.com/article/hierarchical-data-database/2 Storing Hierarchical Data in a Database: ''Modified Pre-order Tree Traversal''], by Gijs van Tulder, at articles.sitepoint.com</ref>
