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Model Tree Structures

MongoDB allows various ways to use tree data structures to model large hierarchical or nested data relationships.

Tree data model for a sample hierarchy of categories.
Model Tree Structures with Parent References
Presents a data model that organizes documents in a tree-like structure by storing references to “parent” nodes in “child” nodes.
Model Tree Structures with Child References
Presents a data model that organizes documents in a tree-like structure by storing references to “child” nodes in “parent” nodes.
Model Tree Structures with an Array of Ancestors
Presents a data model that organizes documents in a tree-like structure by storing references to “parent” nodes and an array that stores all ancestors.
Model Tree Structures with Materialized Paths
Presents a data model that organizes documents in a tree-like structure by storing full relationship paths between documents. In addition to the tree node, each document stores the _id of the nodes ancestors or path as a string.
Model Tree Structures with Nested Sets
Presents a data model that organizes documents in a tree-like structure using the Nested Sets pattern. This optimizes discovering subtrees at the expense of tree mutability.