Contents
How are references saved in a MongoDB document?
MongoDB applications use one of two methods for relating documents: Manual references where you save the _id field of one document in another document as a reference. DBRefs are references from one document to another using the value of the first document’s _id field, collection name, and, optionally, its database name.
How is a tree like structure stored in MongoDB?
This page describes a data model that describes a tree-like structure in MongoDB documents by storing references in the parent-nodes to children nodes. The Child References pattern stores each tree node in a document; in addition to the tree node, document stores in an array the id (s) of the node’s children.
Is it good to keep change history in MongoDB?
This approach is fine though when you’re dealing with small-sized documents and/or don’t update documents very often. Another approach would be to store only the changed fields in a new version.
How is a data model used in MongoDB?
Presents a data model that uses embedded documents to describe one-to-one relationships between connected data. Presents a data model that uses embedded documents to describe one-to-many relationships between connected data. Presents a data model that uses references to describe one-to-many relationships between documents.
When do I delete a document from MongoDB?
“logMessage”: “Success!” MongoDB will automatically delete documents from the log_events collection when the documents’ expireAt value is older than the number of seconds specified in expireAfterSeconds, i.e. 0 seconds older in this case. As such, the data expires at the specified expireAt value.
When to use denormalized data model in MongoDB?
For many use cases in MongoDB, the denormalized data model where related data is stored within a single document will be optimal. However, in some cases, it makes sense to store related information in separate documents, typically in different collections or databases.
Do you need a data store for MongoDB?
There are no technical requirements for this guide. When setting up a data store, your first task is to answer the question: “What data would I like to store and how do the fields relate to each other?”. This guide uses a hypothetical inventory database to track items and their quantities, sizes, tags, and ratings.