Model One-to-Many Relationships with Embedded Documents
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 retreive 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" } ] }