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Version: v1.1.x

belongsToMany

belongsToMany(Model, pivotModel, foreignKey, foreignKeyTarget)​

Many-to-many relations are slightly more complicated than hasOne and hasMany relationships. An example of a many-to-many relationship is a user that has many roles and those roles are also shared by other users in the application. For example, a user may be assigned the role of "Author" and "Editor"; however, those roles may also be assigned to other users as well. So, a user has many roles and a role has many users.

Collection structure​

To define this relationship, three database collections are needed: users, roles, and roleUser. The roleUser collection is derived from the alphabetical order of the related model names and contains userId and roleId columns. This collection is used as an intermediate collection linking the users and roles.

users
    _id - id
    name - string

roles
    _id - id
    name - string

roleUser
    _id - id
    userId - id
    roleId - id

Usage​

Many-to-many relationships are defined by writing a method that returns the result of the belongsToMany method. For example, let's define a roles method on our User model. The first argument passed to this method is the name of the related model class:

import { Mongoloquent } from "mongoloquent";
import Role from "./yourPath/Role";
import RoleUser from "./yourPath/RoleUser";

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

	static roles() {
		return this.belongsToMany(Role, RoleUser, "userId", "roleId");
	}
}

// usage
const user = await User.where("_id", "65ab7e3d05d58a1ad246ee87")
	.with("roles")
	.first();

Also, you can pass collection name as a Model.

The softDelete is disabled in the target model when you pass the collection name as a model.

import { Mongoloquent } from "mongoloquent";

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

	static roles() {
		return this.belongsToMany("roles", "roleUser", "userId", "roleId");
	}
}

// usage
const user = await User.where("_id", "65ab7e3d05d58a1ad246ee87")
	.with("roles")
	.first();

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