# Schema Example: Blog & Comments — MongoDB

Source: https://www.geekswithgeeks.com/en/mongodb/mongo-schema-example

> Two ways to model a blog post with its comments.

## Embedded comments

Good for posts with a handful of comments, always shown together with the post.

```javascript
{
  _id: 1,
  title: "Intro to MongoDB",
  body: "...",
  comments: [
    { user: "bo", text: "Nice post!" },
    { user: "ivy", text: "Very clear." }
  ]
}
```

## Referenced comments

Better when a post can accumulate thousands of comments — each comment is its own document referencing the post.

```javascript
// posts collection
{ _id: 1, title: "Intro to MongoDB", body: "..." }

// comments collection
{ postId: 1, user: "bo", text: "Nice post!" }
{ postId: 1, user: "ivy", text: "Very clear." }
```

## Trade-off recap

Embedding means one fast read but a document that can grow unbounded. Referencing keeps documents small but needs a second query (or `$lookup`) to join data.