Relationship between 3 Models in Laravel

Question

I'm trying to make a relation between 3 Models in Laravel 5.6

Here are my tables

departments

• id
• name

subjects

• id
• name

teachers

• id
• name

teach

• id_teacher
• id_department
• id_subject

The relationship between all tables is many to many.

• Teacher can teach many subjects in many department

• department belongs to many subject

• subject belongs to many department

How to make these relationships inside the Teacher, Department and Subject Models?

Answer 1

You can try something like this:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Department extends Model
{
    /**
     * The teachs that belong to the department.
     */
    public function teachs()
    {
        return $this->belongsToMany('App\Teach', 'teach_department', 'department_id', 'teach_id');
    }
}

class Subject extends Model
{
    /**
     * The teachs that belong to the subject.
     */
    public function teachs()
    {
        return $this->belongsToMany('App\Teach', 'teach_subject', 'subject_id', 'teach_id');
    }
}

class Teacher extends Model
{
    /**
     * The teachs that belong to the teacher.
     */
    public function teachs()
    {
        return $this->belongsToMany('App\Teach', 'teach_teacher', 'teacher_id', 'teach_id');
    }
}

class Teach extends Model
{
    /**
     * The departments that belong to the teach.
     */
    public function departments()
    {
        return $this->belongsToMany('App\Department', 'teach_department', 'teach_id', 'department_id');
    }

    /**
     * The subjects that belong to the teach.
     */
    public function subjects()
    {
        return $this->belongsToMany('App\Subject', 'teach_subject', 'teach_id', 'subject_id');
    }

    /**
     * The teachers that belong to the teach.
     */
    public function teachers()
    {
        return $this->belongsToMany('App\Teacher', 'teach_teacher', 'teach_id', 'teacher_id');
    }
}