materio-base-d7/sites/all/modules/contrib/fields/email/email.install

<?php


/**
 * @file
 * Defines schema for email fields
 */

/**
 * Implements hook_field_schema().
 */
function email_field_schema($field) {
  return array(
    'columns' => array(
      'email' => array(
        'type' => 'varchar',
         'length' => 255,
         'not null' => FALSE,
      ),
    ),
  );
}