Model One-to-Many Relationships with Embedded Documents
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Create a data model that uses embedded documents to describe a one-to-many relationship between connected data. Embedding connected data in a single document can reduce the number of read operations required to obtain data. In general, structure your schema so your application receives all of its required information in a single read operation. For example, you can use the the embedded one-to-many model to describe the following relationships:
Country to major cities
Author to books
Student to classes
Example
The example schema contains three entities, with address one and address two
belonging to the same patron:
// patron document { _id: "joe", name: "Joe Bookreader" } // address one { street: "123 Fake Street", city: "Faketon", state: "MA", zip: "12345" } // address two { street: "1 Some Other Street", city: "Boston", state: "MA", zip: "12345" }
Embedded Document Pattern
In this example the application needs to display information for the patron
and both address objects on a single page. To allow your application to
retrieve all necessary information with a single query, embed the address one
and address two information inside of the patron document:
{ "_id": "joe", "name": "Joe Bookreader", "addresses": [ { "street": "123 Fake Street", "city": "Faketon", "state": "MA", "zip": "12345" }, { "street": "1 Some Other Street", "city": "Boston", "state": "MA", "zip": "12345" } ] }