错误 - 在laravel中从数据库中获取数据时找不到驱动程序

I am getting following error -

could not find driver (SQL: select * from [customer] order by [id] desc)

 'sqlsrv' => [
        'driver' => 'sqlsrv',
        'host' => env('DB_HOST', '127.0.0.1'),
        'port' => env('DB_PORT', '1433'),
        'database' => env('DB_DATABASE', 'Customer'),
        'username' => env('DB_USERNAME', 'SA'),
        'password' => env('DB_PASSWORD', '**********'),
        'charset' => 'utf8',
        'prefix' => '',
    ],

I have also change the default option in database file like below -

  'default' => env('DB_CONNECTION', 'sqlsrv'),

After doing all I am facing mentioned error .