belongsTo(CourseCategory::class); } public function instructor() { return $this->belongsTo(Instructor::class); } public function material() { return $this->hasMany(Material::class); } public function quiz() { return $this->hasMany(Quiz::class); } public function review() { return $this->hasMany(Review::class); } public function discussion() { return $this->hasMany(Discussion::class); } public function enrollment() { return $this->hasMany(Enrollment::class); } public function lesson() { return $this->hasMany(Lesson::class); } }