webform_term_select.install

<?php

/**
 * Implements hook_install().
 * Inserts our new fields into the taxonomy term schema.
 */
function webform_term_select_install() {
    webform_term_select_install_create_fields('taxonomy_term_data', array('wts_visible'));
}

/**
 * Implements hook_uninstall().
 * Drops the fields we declared on the install hook.
 */
function webform_term_select_uninstall() {
    db_drop_field('taxonomy_term_data', 'wts_visible');
}

/**
 * Implements hook_schema().
 * Inserts our new fields into the taxonomy term schema.
 */
function webform_term_select_schema_alter(&$schema) {
    $schema['taxonomy_term_data']['fields']['wts_visible'] = array(
        'type' => 'int',
        'description' => 'Boolean indicating if Webforms is able to see this term.', 
        'unsigned' => TRUE, 
        'not null' => TRUE, 
        'default' => 0
    );
}

/**
 * Utility method for field creation.
 * Allows for multiple fields to be created/edited without having to refresh 
 * the schema on every call. Based on an implementation done by the "i18n" contrib module.
 */
function webform_term_select_install_create_fields($table, $fields) {
  static $schema;
  // Do not force schema refresh more than once per request.
  $schema = drupal_get_schema($table, !isset($schema));
  foreach ($fields as $field) {
    if (!empty($schema['fields'][$field])) {
      if (!db_field_exists($table, $field)) {
        db_add_field($table, $field, $schema['fields'][$field]);
      }
      else {
        // The field exists, make sure field definition is up to date.
        db_change_field($table, $field, $field, $schema['fields'][$field]);
      }
    }
  }
}