如何在同一（数组）laravel中验证多个输入

I have input as shown below:

<input name="keyword[]" type="text" id="keyword" value="" ... required>
<input name="url[]" type="text" id="url" value="" ... required>

This is the result of input request to form an array in it:

array:4 [▼
  "_token" => "LSgeBGHL6QQEkirJFcSLC4T045vb2M4afsi48NeC"
  "category_id" => "1266"
  "keyword" => array:2 [▼
    0 => "test"
    1 => "test"
  ]
  "url" => array:2 [▼
    0 => "/search/test"
    1 => "/search/test"
  ]
]

I want to make a validation if the input array is the same and the data is already in the database before it will not be able to input. I have tried using validation as below, but it didn't work and got an error message.

public function postAdd()
{
    $data = \Input::all();

    $this->validate($data, [
        'keyword.*' => 'required|sometimes|unique',
        'url.*' => 'required|sometimes|unique'
    ]);
}

Please help me to be able to make the same input validation in the array and validate if the inputted data already exists in the database. Thanks!

'keyword.0' => 'required|unique:tablename,fieldname', 'keyword.1' => 'required|unique:tablename,fieldname',

This how to access an validate each member of the array.

I guess I forgot to add if input are same.

'keyword.0' => 'required|unique:tablename,fieldname|different:keyword.1',