Tree structures: Child References

• What are "child" references?

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  • A special property "children"
  • Stores an array of _ids of the document one level below in the tree

• Why use child references?

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  • Used to navigate tree-structured or hierarchical data

• How do you implement child references in MongoDB?

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  • When you save a document, include a "children" property
    which stores an array _ids one level below

• Can you have both parent and child references?

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  • Yes, as shown in the example