source: sipes/cord/modules/user/user.install @ 8a8efa8

<?php

/**
 * Implementation of hook_schema().
 */
function user_schema() {
  $schema['access'] = array(
    'description' => 'Stores site access rules.',
    'fields' => array(
      'aid' => array(
        'type' => 'serial',
        'not null' => TRUE,
        'description' => 'Primary Key: Unique access ID.',
      ),
      'mask' => array(
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
        'description' => 'Text mask used for filtering access.',
      ),
      'type' => array(
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
        'description' => 'Type of access rule: name, mail or host.',
      ),
      'status' => array(
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'size' => 'tiny',
        'description' => 'Whether rule is to allow(1) or deny(0) access.',
      ),
    ),
    'primary key' => array('aid'),
  );

  $schema['authmap'] = array(
    'description' => 'Stores distributed authentication mapping.',
    'fields' => array(
      'aid' => array(
        'description' => 'Primary Key: Unique authmap ID.',
        'type' => 'serial',
        'unsigned' => TRUE,
        'not null' => TRUE,
      ),
      'uid' => array(
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'description' => "User's {users}.uid.",
      ),
      'authname' => array(
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
        'description' => 'Unique authentication name.',
      ),
      'module' => array(
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
        'description' => 'Module which is controlling the authentication.',
      ),
    ),
    'unique keys' => array('authname' => array('authname')),
    'primary key' => array('aid'),
  );

  $schema['permission'] = array(
    'description' => 'Stores permissions for users.',
    'fields' => array(
      'pid' => array(
        'type' => 'serial',
        'not null' => TRUE,
        'description' => 'Primary Key: Unique permission ID.',
      ),
      'rid' => array(
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
        'description' => 'The {role}.rid to which the permissions are assigned.',
      ),
      'perm' => array(
        'type' => 'text',
        'not null' => FALSE,
        'size' => 'big',
        'description' => 'List of permissions being assigned.',
      ),
      'tid' => array(
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
        'description' => 'Originally intended for taxonomy-based permissions, but never used.',
      ),
    ),
    'primary key' => array('pid'),
    'indexes' => array('rid' => array('rid')),
  );

  $schema['role'] = array(
    'description' => 'Stores user roles.',
    'fields' => array(
      'rid' => array(
        'type' => 'serial',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'description' => 'Primary Key: Unique role id.',
      ),
      'name' => array(
        'type' => 'varchar',
        'length' => 64,
        'not null' => TRUE,
        'default' => '',
        'description' => 'Unique role name.',
      ),
    ),
    'unique keys' => array('name' => array('name')),
    'primary key' => array('rid'),
  );

  $schema['users'] = array(
    'description' => 'Stores user data.',
    'fields' => array(
      'uid' => array(
        'type' => 'serial',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'description' => 'Primary Key: Unique user ID.',
      ),
      'name' => array(
        'type' => 'varchar',
        'length' => 60,
        'not null' => TRUE,
        'default' => '',
        'description' => 'Unique user name.',
      ),
      'pass' => array(
        'type' => 'varchar',
        'length' => 32,
        'not null' => TRUE,
        'default' => '',
        'description' => "User's password (md5 hash).",
      ),
      'mail' => array(
        'type' => 'varchar',
        'length' => 64,
        'not null' => FALSE,
        'default' => '',
        'description' => "User's email address.",
      ),
      'mode' => array(
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'size' => 'tiny',
        'description' => 'Per-user comment display mode (threaded vs. flat), used by the {comment} module.',
      ),
      'sort' => array(
        'type' => 'int',
        'not null' => FALSE,
        'default' => 0,
        'size' => 'tiny',
        'description' => 'Per-user comment sort order (newest vs. oldest first), used by the {comment} module.',
      ),
      'threshold' => array(
        'type' => 'int',
        'not null' => FALSE,
        'default' => 0,
        'size' => 'tiny',
        'description' => 'Previously used by the {comment} module for per-user preferences; no longer used.',
      ),
      'theme' => array(
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
        'description' => "User's default theme.",
      ),
      'signature' => array(
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
        'description' => "User's signature.",
      ),
      'signature_format' => array(
        'type' => 'int',
        'size' => 'small',
        'not null' => TRUE,
        'default' => 0,
        'description' => 'The {filter_formats}.format of the signature.',
      ),
      'created' => array(
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'description' => 'Timestamp for when user was created.',
      ),
      'access' => array(
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'description' => 'Timestamp for previous time user accessed the site.',
      ),
      'login' => array(
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'description' => "Timestamp for user's last login.",
      ),
      'status' => array(
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'size' => 'tiny',
        'description' => 'Whether the user is active(1) or blocked(0).',
      ),
      'timezone' => array(
        'type' => 'varchar',
        'length' => 8,
        'not null' => FALSE,
        'description' => "User's timezone.",
      ),
      'language' => array(
        'type' => 'varchar',
        'length' => 12,
        'not null' => TRUE,
        'default' => '',
        'description' => "User's default language.",
      ),
      'picture' => array(
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
        'description' => "Path to the user's uploaded picture.",
      ),
      'init' => array(
        'type' => 'varchar',
        'length' => 64,
        'not null' => FALSE,
        'default' => '',
        'description' => 'Email address used for initial account creation.',
      ),
      'data' => array(
        'type' => 'text',
        'not null' => FALSE,
        'size' => 'big',
        'description' => 'A serialized array of name value pairs that are related to the user. Any form values posted during user edit are stored and are loaded into the $user object during user_load(). Use of this field is discouraged and it will likely disappear in a future version of Drupal.',
      ),
    ),
    'indexes' => array(
      'access' => array('access'),
      'created' => array('created'),
      'mail' => array('mail'),
    ),
    'unique keys' => array(
      'name' => array('name'),
    ),
    'primary key' => array('uid'),
  );

  $schema['users_roles'] = array(
    'description' => 'Maps users to roles.',
    'fields' => array(
      'uid' => array(
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
        'description' => 'Primary Key: {users}.uid for user.',
      ),
      'rid' => array(
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
        'description' => 'Primary Key: {role}.rid for role.',
      ),
    ),
    'primary key' => array('uid', 'rid'),
    'indexes' => array(
      'rid' => array('rid'),
    ),
  );

  return $schema;
}