source: sipes/modules_contrib/captcha/captcha.install @ 6e81fb4

<?php

/**
 * @file
 * Install, update and uninstall functions for the CAPTCHA module.
 */

/**
 * Implementation of hook_schema().
 */
function captcha_schema() {
  // Table for positions and types of the challenges.
  $schema['captcha_points'] = array(
    'description' => 'This table describes which challenges should be added to which forms.',
    'export' => array(
      'key' => 'form_id',
      'identifier' => 'captcha',
      'default hook' => 'captcha_default_points',  // Function hook name.
      'status' => 'mark_status',
      'api' => array(
        'owner' => 'captcha',
        'api' => 'captcha',  // Base name for api include files.
        'minimum_version' => 1,
        'current_version' => 1,
      ),
    ),
    'fields' => array(
      'form_id' => array(
        'description' => 'The form_id of the form to add a CAPTCHA to.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'module' => array(
        'description' => 'The module that provides the challenge.',
        'type' => 'varchar',
        'length' => 64,
      ),
      'captcha_type' => array(
        'description' => 'The challenge type to use.',
        'type' => 'varchar',
        'length' => 64,
      ),
    ),
    'primary key' => array('form_id'),
  );
  // Table for the CAPTCHA sessions.
  $schema['captcha_sessions'] = array(
    'description' => 'Stores the data about CAPTCHA sessions (solution, IP address, timestamp, ...).',
    'fields' => array(
      'csid' => array(
        'description' => 'CAPTCHA session ID.',
        'type' => 'serial',
        'not null' => TRUE,
      ),
      'token' => array(
        'description' => 'One time CAPTCHA token.',
        'type' => 'varchar',
        'length' => 64,
        'not null' => FALSE,
      ),
      'uid' => array(
        'description' => "User's {users}.uid.",
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'sid' => array(
        'description' => "Session ID of the user.",
        'type' => 'varchar',
        'length' => 64,
        'not null' => TRUE,
        'default' => '',
      ),
      'ip_address' => array(
        'description' => 'IP address of the visitor.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => FALSE,
      ),
      'timestamp' => array(
        'description' => 'A Unix timestamp indicating when the challenge was generated.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'form_id' => array(
        'description' => 'The form_id of the form where the CAPTCHA is added to.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
      ),
      'solution' => array(
        'description' => 'Solution of the challenge.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'status' => array(
        'description' => 'Status of the CAPTCHA session (unsolved, solved, ...)',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'attempts' => array(
        'description' => 'The number of attempts.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      )
    ),
    'primary key' => array('csid'),
    'indexes' => array(
      'csid_ip' => array('csid', 'ip_address'),
    ),
  );

  return $schema;
}

/**
 * Implementation of hook_requirements().
 */
function captcha_requirements($phase) {
  $requirements = array();
  $t = get_t();
  if ($phase == 'runtime') {
    // Show the wrong response counter in the status report.
    $requirements['captcha_wrong_response_counter'] = array(
      'title' => $t('CAPTCHA'),
      'value' => format_plural(
        variable_get('captcha_wrong_response_counter', 0),
        'Already 1 blocked form submission',
        'Already @count blocked form submissions'
      ),
      'severity' => REQUIREMENT_INFO,
    );
  }
  return $requirements;
}

/**
 * Implementation of hook_install().
 */
function captcha_install() {
  $t = get_t();
  drupal_install_schema('captcha');


  // Be friendly to your users: what to do after install?
  drupal_set_message($t('You can now <a href="!captcha_admin">configure the CAPTCHA module</a> for your site.',
    array('!captcha_admin' => url('admin/user/captcha'))), 'status');

  // Explain to users that page caching may be disabled.
  if (variable_get('cache', CACHE_DISABLED) != CACHE_DISABLED) {
    drupal_set_message($t('Note that the CAPTCHA module disables <a href="!performance_admin">page caching</a> of pages that include a CAPTCHA challenge.',
      array('!performance_admin' => url('admin/settings/performance'))), 'warning');
  }

}

/**
 * Implementation of hook_uninstall().
 */
function captcha_uninstall() {
  drupal_uninstall_schema('captcha');
  db_query("DELETE FROM {variable} WHERE name LIKE 'captcha_%'");
  cache_clear_all('variables', 'cache');
}

/**
 * Implementation of hook_update_N()
 */
function captcha_update_1() {
  $items = array();
  switch ($GLOBALS['db_type']) {
    case 'mysql':
    case 'mysqli':
      $items[] = update_sql("CREATE TABLE {captcha_points} (
        form_id varchar(128) NOT NULL,
        module varchar(64) default NULL,
        type varchar(64) default NULL,
        PRIMARY KEY (form_id)
        ) /*!40100 DEFAULT CHARACTER SET utf8 */;"
      );
      $succes = TRUE;
      break;
    case 'pgsql':
      $items[] = update_sql("CREATE TABLE {captcha_points} (
        form_id varchar(128) NOT NULL,
        module varchar(64) default NULL,
        type varchar(64) default NULL,
        PRIMARY KEY (form_id)
        );"
      );
      $succes = TRUE;
      break;
    default:
      drupal_set_message(t('Unsupported database.'), 'error');
      $succes = FALSE;
      break;
  }
  if ($succes) {
    // insert some defaults
    $form_ids = array('comment_form', 'contact_mail_user', 'contact_mail_page',
      'user_register', 'user_pass');
    foreach ($form_ids as $form_id) {
      $items[] = update_sql("INSERT INTO {captcha_points} (form_id, module, type) VALUES ('$form_id', NULL, NULL)");
    }
  }
  return $items;
}

/**
 * Implementation of hook_update_N()
 */
function captcha_update_2() {
  $items = array();
  // insert some defaults
  $form_ids = array('user_login', 'user_login_block');
  foreach ($form_ids as $form_id) {
    $items[] = update_sql("INSERT INTO {captcha_points} (form_id, module, type) VALUES ('$form_id', NULL, NULL)");
  }
  return $items;
}

/**
 * Implementation of hook_update_N()
 */
function captcha_update_6200() {
  $items = array();

  // Table for the CAPTCHA sessions.
  $schema['captcha_sessions'] = array(
    'description' => 'Stores the data about CAPTCHA sessions (solution, IP address, timestamp, ...).',
    'fields' => array(
      'csid' => array(
        'description' => 'CAPTCHA session ID.',
        'type' => 'serial',
        'not null' => TRUE,
      ),
      'uid' => array(
        'description' => "User's {users}.uid.",
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'sid' => array(
        'description' => "Session ID of the user.",
        'type' => 'varchar',
        'length' => 64,
        'not null' => TRUE,
        'default' => '',
      ),
      'ip_address' => array(
        'description' => 'IP address of the visitor.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => FALSE,
      ),
      'timestamp' => array(
        'description' => 'A Unix timestamp indicating when the challenge was generated.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'form_id' => array(
        'description' => 'The form_id of the form where the CAPTCHA is added to.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
      ),
      'solution' => array(
        'description' => 'Solution of the challenge.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'status' => array(
        'description' => 'Status of the CAPTCHA session (unsolved, solved, ...)',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'attempts' => array(
        'description' => 'The number of attempts.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      )
    ),
    'primary key' => array('csid'),
    'indexes' => array(
      'csid_ip' => array('csid', 'ip_address'),
    ),
  );

  db_create_table($items, 'captcha_sessions', $schema['captcha_sessions']);

  return $items;
}

/**
 * Implementation of hook_update_N()
 * Change the captcha points with the old text CAPTCHA, which was
 * removed from the 6.x-2.x branch, to the simple math CAPTCHA.
 */
function captcha_update_6201() {
  $items = array();
  $items[] = update_sql("UPDATE {captcha_points} SET module = 'captcha', type = 'Math' WHERE module = 'text_captcha' AND type = 'Text';");
  return $items;
}


/**
 * Implementation of hook_update_N()
 * Add a CAPTCHA token column to captcha_sessions table.
 */
function captcha_update_6202() {
  $ret = array();
  db_add_column($ret, 'captcha_sessions', 'token', 'varchar(64)');
  return $ret;
}

/**
 * Implementation of hook_update_N()
 * Rename the type field to captcha_type in captcha_points.
 */
function captcha_update_6203() {
  $ret = array();
  db_change_field($ret, 'captcha_points', 'type', 'captcha_type', array('type' => 'varchar', 'length' => 64));
  return $ret;
}