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Version: v2.x.x

One to Many

One to Many (Polymorphic)​

Collection Structure​

A one-to-many polymorphic relation is similar to a typical one-to-many relation; however, the child model can belong to more than one type of model using a single association. For example, imagine users of your application can "comment" on posts and videos. Using polymorphic relationships, you may use a single comments collection to contain comments for both posts and videos. First, let's examine the collection structure required to build this relationship:

posts
  _id - ObjectId
  title - string
  body - text

videos
  _id - ObjectId
  title - string
  url - string

comments
  _id - ObjectId
  body - text
  commentableId - ObjectId
  commentableType - string

Model Structure​

Next, let's examine the model definitions needed to build this relationship:

// Comment.js
import { Mongoloquent } from "mongoloquent";

class Comment extends Mongoloquent {
	static collection = "comments";
	static softDelete = true;
	static timestamps = true;
}
// Post.js
import { Mongoloquent } from "mongoloquent";
import Comment from "./yourPath/Comment";

class Post extends Mongoloquent {
	static collection = "posts";
	static softDelete = true;
	static timestamps = true;

	/**
	 * Get all of the post's comments.
	 */
	static comments() {
		return this.morphMany(Comment, "commentable");
	}
}
// Video.js
import { Mongoloquent } from "mongoloquent";
import Comment from "./yourPath/Comment";

class Video extends Mongoloquent {
	static collection = "videos";
	static softDelete = true;
	static timestamps = true;

	/**
	 * Get all of the video's comments.
	 */
	static comments() {
		return this.morphMany(Comment, "commentable");
	}
}

Retrieving the Relationship​

Once your database collection and models are defined, you may access the relationships via your model's dynamic relationship properties. For example, to access all of the comments for a post, we can use the comments dynamic property:

import Post from "./yourPath/Post";

const post = await Post.with("comments").find("10ab7e3d05d58a1ad250dd90");

// your relationship data can accessed in the data property
console.log(post.data);
import Video from "./yourPath/Video";

const video = await Video.with("comments").find("11bb7e3d05d58a1ad250dd99");

// your relationship data can accessed in the data property
console.log(video.data);

Monggoloquent can also select or exclude certain related model keys

import Post from "./yourPath/Post";

// with select keys
await Post.with("comments", {
	select: ["body"]
}).find("56ab7e3d05d58a1ad250dd56");

// with exclude keys
await Post.with("comments", {
	exclude: ["body"]
}).find("56ab7e3d05d58a1ad250dd56");
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