laravel defaultString code example

Example 1: laravel migation error

use Illuminate\Support\Facades\Schema;

public function boot()
{
    Schema::defaultStringLength(191);
}

Example 2: ERROR 1071 (42000) at line 76: Specified key was too long; max key length is 767 bytes laravel

'charset' => 'utf8mb4',
'collation' => 'utf8mb4_unicode_ci',