Laravel: Validation unique on update

One simple solution.

In your Model

protected $rules = [
    'email_address' => 'sometimes|required|email|unique:users',
    ..
];

In your Controller, action:update

...
$rules = User::$rules;
$rules['email_address'] = $rules['email_address'] . ',id,' . $id;
$validationCertificate  = Validator::make($input, $rules); 

Just a side note, most answers to this question talk about email_address while in Laravel's inbuilt auth system, the email field name is just email. Here is an example how you can validate a unique field, i.e. an email on the update:

In a Form Request, you do like this:

public function rules()
{
  return [
      'email' => 'required|email|unique:users,email,'.$this->user->id,
  ];
}

Or if you are validating your data in a controller directly:

public function update(Request $request, User $user)
{
  $request->validate([
      'email' => 'required|email|unique:users,email,'.$user->id,
  ]);
}

Update: If you are updating the signed in user and aren't injecting the User model into your route, you may encounter undefined property when accessing id on $this->user. In that case, use:

public function rules()
    {
      return [
          'email' => 'required|email|unique:users,email,'.$this->user()->id,
      ];
    }

A more elegant way since Laravel 5.7 is:

public function rules()
{
    return [
        'email' => ['required', 'email', \Illuminate\Validation\Rule::unique('users')->ignore($this->user()->id)]
    ];
}

P.S: I have added some other rules, i.e. required and email, in order to make this example clear for newbies.

There is an elegant way to do this. If you are using Resource Controllers, your link to edit your record will look like this:

/users/{user}/edit OR /users/1/edit

And in your UserRequest, the rule should be like this :

public function rules()
{
    return [
        'name' => [
            'required',
            'unique:users,name,' . $this->user
        ],
    ];
}

Or if your link to edit your record look like this:

/users/edit/1

You can try this also:

public function rules()
{
    return [
        'name' => [
            'required',
            'unique:users,name,' . $this->id
        ],
    ];
}