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One to One

One to One Relationship​

A one-to-one relationship is a very basic type of database relationship. For example, a User model might be associated with one Phone model. To define this relationship, we will place a phone method on the User model. The phone method should call the hasOne method and return its result.

import { Mongoloquent } from "mongoloquent";
import Phone from "./yourPath/Phone";

class User extends Mongoloquent {
	static collection = "users";

	static phone() {
		return this.hasOne(Phone, "userId", "_id");
	}
}

The first argument passed to the hasOne method is the name of the related model class. Once the relationship is defined, we may retrieve the related record using Mongoloquent's dynamic properties. Dynamic properties allow you to access relationship methods as if they were properties defined on the model:

import User from "./yourPath/User";

const user = await User.with("phone").find("65ab7e3d05d58a1ad246ee87");

// you can access your data in the data property
console.log(user.data);

Additionally, Mongoloquent assumes that the foreign key should have a value matching the primary key column of the parent. In other words, Mongoloquent will look for the value of the user's _id column in the userId column of the Phone record.

Defining the Inverse of the Relationship​

So, we can access the Phone model from our User model. Next, let's define a relationship on the Phone model that will let us access the user that owns the phone. We can define the inverse of a hasOne relationship using the belongsTo method:

import { Mongoloquent } from "mongoloquent";
import User from "./yourPath/User";

class Phone extends Mongoloquent {
	static collection = "phones";

	static user() {
		return this.belongsTo(User, "userId", "_id");
	}
}

// usage
const phone = await Phone.with("user").find("10ab7e3d05d58a1ad250dd90");

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

When invoking the user method, Mongoloquent will attempt to find a User model that has an _id which matches the userId column on the Phone model.

Monggoloquent can also select or exclude certain related model keys

import User from "./yourPath/User";

// with select keys
await User.with("phone", {
	select: ["number"],
}).find("65ab7e3d05d58a1ad246ee87");

// with exclude keys
await User.with("phone", {
	exclude: ["number"],
}).find("65ab7e3d05d58a1ad246ee87");

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