Model Tree Structures

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

• Model Tree Structures with Parent References
• Presents a data model that organizes documents in a tree-likestructure by storing referencesto “parent” nodes in “child” nodes.
• Model Tree Structures with Child References
• Presents a data model that organizes documents in a tree-likestructure by storing referencesto “child” nodes in “parent” nodes.
• Model Tree Structures with an Array of Ancestors
• Presents a data model that organizes documents in a tree-likestructure by storing referencesto “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-likestructure by storing full relationship paths between documents. Inaddition to the tree node, each document stores the _id of thenodes ancestors or path as a string.
• Model Tree Structures with Nested Sets
• Presents a data model that organizes documents in a tree-likestructure using the Nested Sets pattern. This optimizesdiscovering subtrees at the expense of tree mutability.