如何在laravel中使用外键从另一个表中获取所需的列

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

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

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

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

$user = User::find(1);
$profile = $user->profile; // 获取用户的配置文件

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

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

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

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

$user = User::find(1);
$posts = $user->posts; // 获取用户的所有帖子

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

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

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

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

$user = User::find(1);
$roles = $user->roles; // 获取用户的所有角色

ALTER TABLE profiles
ADD CONSTRAINT fk_user_profile
FOREIGN KEY (user_id) REFERENCES users(id);

// User.php
public function profile()
{
    return $this->hasOne(Profile::class, 'user_id', 'id');
}

// Profile.php
public function user()
{
    return $this->belongsTo(User::class, 'user_id', 'id');
}