User::find(1, ['name', 'email']);
User::findOrFail(1, ['name', 'email']);

$user = User::find(1);
$newUser = $user->replicate();
$newUser->save();

$user = User::find(1);
$sameUser = User::find(1);
$diffUser = User::find(2);
$user->is($sameUser); // true
$user->is($diffUser); // false;

$user = User::find(1);
$user->name; // 'Peter'
// 如果 name 更新过，比如由 peter 更新为 John
$user->refresh();
$user->name; // John

$user = App\User::first();
$user->name;    // John
//
$updatedUser = $user->fresh(); 
$updatedUser->name;  // Peter
$user->name;    // John

class User extends Model
{
 public function phone()
 {
  return $this->hasOne('App\Phone');
 }
}
$user = User::first();
$user->name = "Peter";
$user->phone->number = '1234567890';
$user->save(); // 只更新 User Model
$user->push(); // 更新 User 和 Phone Model

class User extends Model
{
 use SoftDeletes;
  * deleted_at 字段.
  *
  * @var string
  */
 const DELETED_AT = 'is_deleted';
}

class User extends Model
{
 use SoftDeletes;
 
 public function getDeletedAtColumn(){
  return 'is_deleted';
 }
}

$user = User::first();
$user->name; // John
$user->name = 'Peter';
$user->save();

dd($user->getChanges());
// 输出：
[
 'name' => 'John',
 'updated_at' => '...'
]

$user = User::first();
$user->name;    // John
$user->isDirty();  // false 
$user->name = 'Peter'; 
$user->isDirty();  // true
$user->getDirty();  // ['name' => 'Peter']
$user->save();   
$user->isDirty();  // false

$user = App\User::first();
$user->name;     //John
$user->name = "Peter";   //Peter
$user->getOriginal('name'); //John
$user->getOriginal();   //Original $user record