I have created a custom form as below. And the user has to fill all the fields for the submission(I am storing all the fields after submission).

Question is how do i check if the email address has already been entered ?

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1 Answer 1


One way of doing that is using the hook_form_alter and add the custom validation function, and in that custom validation you can check if the enterd email already exists in the database than set error, somewhat like below:

 * Implements hook_form_alter.
function MYMODULE_form_alter(&$form, &$form_state, $form_id) {
  // Check the form id of your form.
  if ($form_id === 'YOUR_FORM_ID_WHICH_YOU_WANT_TO_EDIT') {
    $form['#validate'][] = 'check_email_address_exists';

function check_email_address_exists(&$form, &$form_state) {
  // Get the value of email field. if you are under than use: "dpm($form_state['values'])"
  $email_entered = $form_state['values']['EMAIL_FIELD_NAME'];

  // Generate the query somewhat like below, For Example I am using users table's "uid".
  $query = db_select('users', 'u');
  $query->fields('u', array('uid'));
  $query->condition('u.mail', $email_entered);

  // This will return the count of the fields found.
  $row_count = $query->countQuery()->execute()->fetchField(); 

  if (isset($row_count) && ($row_count > 0)) {
    form_set_error('EMAIL_ADDRESS_FIELD_NAME', t('This email already exists, please try with another email  address!'));

In order it to work you have to change the values as per you requirement, and don't forget to modify the db_select query as per your requirement, and last CLEAR THE CACHE after implementing the same.

  • No need to use alter when he is the one who created the form in the first place.
    – Mołot
    Commented Oct 22, 2013 at 12:56
  • Yeah right if one has created the custom form than the validation can be added directly instead of using the hook_form_alter, otherwise we can use hook_form_alter to add the custom validator. :) Commented Oct 22, 2013 at 12:59

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