How Do I Reference A Schema in Mongoose?

Introduction

Hi there, welcome to my blog once again. I feel excited while writing this article after a long time of taking a break.

Please join me as we learn together how to reference a schema using Mongoose.

What is a Schema?

A Schema is a blueprint for defining data structure in Mongoose. It tells you what the data will look like and the accepted format.

Example:

  const userSchema = new Schema({
    full_name: {
      type: String,
      required: true,
    },
   email: {
      type: String,
      required: true,
    }
    password: {
      type: String,
      required: true,
    }
  });

 mongoose.model('user', userSchema);

With the example above, you will notice that a User is required to have a name in full, email, and password. This is a type of blueprint.

How do we reference another schema?

Let's use a user's post on Facebook as an example. Users on Facebook write and comment on posts all the time, now how do we connect a user with posts? We reference it.

We are going to create a postSchema. We are going to use the ref property and Mongoose.schema.ObjectId to reference the userSchema.

 const postSchema = new Schema({
    post: String,
    postMadeBy: {
      type: Mongoose.schema.ObjectId,
      ref:  'user',
      },
 });

mongoose.model('post', postSchema);

This is our postSchema.

Explanation:

You will observe that it contains post and postMadeBy properties. postMadeBy has it's own properties of type and ref which points to Mongoose.schema.ObjectId and user respectively.

When a user makes a post, the id of that user is attached alongside the post made and referenced in the database. So it will be something like this:-

  {
      "_id" : ObjectId("6086b0f46aae7f44f2fc1b42"),
      "post" : "Hello World!!",
      "postMadeBy" : ObjectId("608d7be038513c2c08c5db12"),
      "__v" : 0
  }

You can achieve it too

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