I'm still working on user registration with Drupal 7 and Services 3 and I got a weird Error 500 :

Integrity constraint violation: 1048 Column 'uid' cannot be null

Here is the code I'm using :

// REST Server URL for auth
$request_url = SERVER_URL . 'rest/user/register';

// User data
$user_data = array(
  'name' => 'newuser',
  'mail' => '[email protected]',
  'pass' => 'newpass',
  'field_city' => array('und' => array('0' => array('value' => 'NA'))),

$user_data = json_encode($user_data);
// cURL
$curl = curl_init($request_url);
curl_setopt($curl, CURLOPT_HTTPHEADER, array('Accept: application/json', 'Content-Type: application/json'));
curl_setopt($curl, CURLOPT_POST, TRUE);
curl_setopt($curl, CURLOPT_POSTFIELDS, $user_data);
curl_setopt($curl, CURLOPT_HEADER, TRUE);
curl_setopt($curl, CURLOPT_VERBOSE, true);

$response = curl_exec($curl);

$http_code = curl_getinfo($curl, CURLINFO_HTTP_CODE);
  if ($http_code == 200) {
  return json_decode($response);
else {
  $http_message = curl_error($curl);
  return $http_message;

Is there something I'm doing wrong ?

  • It says you can't set uid to null, or omit it. But I don't see where you are setting it. So it looks like you are omitting it. Or am I missing something? Also, for uid there should be some kind of auto increment and null should be allowed, and mean "generate next one". Was you altering things directly in database?
    – Mołot
    Jun 12, 2015 at 10:52
  • Hello Molot and thanks for your quick comment, but I didn't know the uid at that point, cause I'm trying to create the user, so I can't pass it to $user_data. The table "users" isn't auto-incremented and Null is not allowed, but this is not a problem when I create a new user with the Drupal form or with Drush. This error only appears when I try to create a user using Services, and I prefer not to alter this table.
    – nieud
    Jun 12, 2015 at 11:02

1 Answer 1


I think that on the other side of your code you are trying to save the user. So, to create a new user using user_save() function you have to left the first parameter blank so a new user is created. Also, add the parameter true to your json_decode($response, true) to obtain an array rather than an object.

$account = user_save('', $fields);

  • Hello MMC, yes I'm trying to save the user but with Drupal Services API. So I won't use user_save() neither bootstrap Drupal.
    – nieud
    Jun 15, 2015 at 9:41

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