为什么在PHP中为数组分配新值会失败？

Consider:

array (size=1)
  0 =>
    array (size=5)
      'name' => string '15268459735 Farming and Projects XXXXX' (length=38)
      'region' => string '2' (length=1)
      'entitynumber' => string '2012/002086/24' (length=14)
      'ownership' => string '6' (length=1)
      'id' => string '26249' (length=5)

Why does the following still return the same array without the owner element?

foreach ($result as $row)
{
    $row['owner'] = 1;
}

Try passing the array by reference:

foreach ($result as &$row) {
    $row['owner'] = 1;
}