laravel orm

https://laravelacademy.org/post/9584.html

一对一：

class User extends Model
{
    public function profile()
    {
        return $this->hasOne(Profile::class);
    }
}

class Profile extends Model
{
    public function user()
    {
        return $this->belongsTo(User::class);
    }
}

一对多：

 class Post extends Model { 
　　public function comments() {
　　 return $this->hasMany(Comment::class);
　　 } }

 class Comment extends Model {
　　 public function post() {
　　　　 return $this->belongsTo(Post::class);
　　　　 } }

多对多：

class User extends Model
{
    public function roles()
    {
        return $this->belongsToMany(Role::class);
    }
}

class Role extends Model
{
    public function users()
    {
        return $this->belongsToMany(User::class);
    }
}