MongoDB Documentation, Release 3.0.4 { _id: "joe", name: "Joe Bookreader" } { patron_id: "joe", street: "123 Fake Street", city: "Faketon", state: "MA", zip: "12345" } If the address data is frequently retrieved with the name information, then with referencing, your application needs to issue multiple queries to resolve the reference. The better data model would be to embed the address data in the patron data, as in the following document: With the embedded data model, your application can retrieve the complete patron information with one query. Data in MongoDB has a flexible schema . Collections do not enforce document structure. Decisions that affect how you model data can affect application performance and database capacity. See Data Modeling Concepts (page 145) for a full high level overview of data modeling in MongoDB. This document describes a data model that uses embedded (page 146) documents to describe relationships between connected data. Consider the following example that maps patron and multiple address relationships. The example illustrates the advantage of embedding over referencing if you need to view many data entities in context of another. In this one-to- many relationship between patron and address data, the patron has multiple address entities. In the normalized data model, the address documents contain a reference to the patron document. Model One-to-Many Relationships with Embedded Documents Overview Pattern { _id: "joe", name: "Joe Bookreader", address: { street: "123 Fake Street", city: "Faketon", state: "MA", zip: "12345" } } { _id: "joe", name: "Joe Bookreader" } { patron_id: "joe", 153 4.3. Data Model Examples and Patterns