Modeling One-to-Many Relationships in Java with MongoDB

Thu, 26 Mar 2026 15:50:30 +0000

In a relational database, modeling a one-to-many relationship is straightforward: you create two tables and connect them with a foreign key. When you need the data together, you write a JOIN. In MongoDB, you have a choice, and that choice has a direct impact on your application’s performance, scalability, and maintainability.

Consider a common scenario: a BlogPost that has many Comment objects. In Java, this is a natural List<Comment> field on the post. But when it comes time to persist that relationship in MongoDB, you need to decide how to store it. Should the comments live inside the blog post document? Or should they sit in their own collection, connected by references?

Arthur Ribeiro on foojay.io - Friends of OpenJDK

Modeling One-to-Many Relationships in Java with MongoDB