laravel validation rule value must be same as given code example

Example: laravel unique validation

/**
 * Store a new blog post.
 *
 * @param  Request  $request
 * @return Response
 */

public function store(Request $request)
{
    $validatedData = $request->validate([
        'title' => 'required|unique:posts|max:255',
        'body' => 'required',
    ]);

    // The blog post is valid...
}