Embedding vs Referencing in MongoDB

1. Introduction

In MongoDB, data modeling is crucial for effective database design. Two primary strategies for data modeling are embedding and referencing. This lesson breaks down these concepts, providing clarity on when to use each approach.

2. Embedding

{
    "_id": 1,
    "title": "My First Blog Post",
    "content": "Hello, world!",
    "comments": [
        { "user": "Alice", "message": "Great post!" },
        { "user": "Bob", "message": "Thanks for sharing!" }
    ]
}

3. Referencing

{
    "_id": 1,
    "title": "My First Blog Post",
    "content": "Hello, world!"
}

{
    "_id": 1,
    "postId": 1,
    "user": "Alice",
    "message": "Great post!"
}

4. Best Practices

When deciding between embedding and referencing, consider the following:

• Use embedding when:
• Data is frequently accessed together.
• Data is relatively small and does not grow unbounded.
• Use referencing when:
• Data is large or grows unbounded.
• Data is accessed independently or shared across multiple documents.

5. Flowchart

graph TD;
    A[Is data frequently accessed together?] -->|Yes| B[Use Embedding];
    A -->|No| C[Is data large or grows unbounded?];
    C -->|Yes| D[Use Referencing];
    C -->|No| B;

6. FAQ