# Database Relationship Types

* **One-to-One**: A user has one profile (e.g., `/users/1/profile`).
* **One-to-Many**: An author has many books (`/authors/1/books`).
* **Many-to-Many**: Projects and team members (`/projects/1/team-members`).
  * _**UPDATE (10/2/23):**  We may be moving away from nesting for these relationships per Jase's new suggestion_

### Relate&#x64;**:**

* [**Routes setup (BACKEND style guide)**](../backend/file-setups/routes-routes.rb) (i.e. `routes.rb`)
* [**Controller Setup (BACKEND style guide)**](../backend/file-setups/controllers-x_controller.rb) (e.g. `projects_controller.rb`)
