MongoDB Schema Design: Embedding

What is Embedding in MongoDB?

Embedding means including related data as nested documents inside a parent document.

Instead of splitting data across multiple collections, embedding keeps related information together.

This approach leverages MongoDB's flexible document model to represent complex data structures naturally.

• Stores related data inside a single document.
• Uses nested objects or arrays for related entities.
• Simplifies data retrieval by reducing the need for joins.

When to Use Embedding

Embedding is ideal when related data is frequently accessed together and the relationship is one-to-few.

It works well for data that changes together or has a bounded size.

Choosing embedding improves query performance and reduces complexity.

• One-to-few relationships (e.g., a blog post and its comments).
• Data that is read and written together.
• Data with limited size to avoid large documents.

Example of Embedding

Consider a blog application where each post has multiple comments.

Embedding comments inside the post document allows fetching the post and its comments in a single query.

Embedding Example Document

Here is a sample MongoDB document embedding comments inside a blog post: