system_schema

system_schema()

function system_schema() {
  $schema['key_value'] = array(
    'description' => 'Generic key-value storage table. See the state system for an example.',
    'fields' => array(
      'collection' => array(
        'description' => 'A named collection of key and value pairs.',
        'type' => 'varchar_ascii',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'name' => array(
        'description' => 'The key of the key-value pair. As KEY is a SQL reserved keyword, name was chosen instead.',
        'type' => 'varchar_ascii',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'value' => array(
        'description' => 'The value.',
        'type' => 'blob',
        'not null' => TRUE,
        'size' => 'big',
      ),
    ),
    'primary key' => array('collection', 'name'),
  );

  $schema['key_value_expire'] = array(
    'description' => 'Generic key/value storage table with an expiration.',
    'fields' => array(
      'collection' => array(
        'description' => 'A named collection of key and value pairs.',
        'type' => 'varchar_ascii',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'name' => array(
        // KEY is an SQL reserved word, so use 'name' as the key's field name.
        'description' => 'The key of the key/value pair.',
        'type' => 'varchar_ascii',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'value' => array(
        'description' => 'The value of the key/value pair.',
        'type' => 'blob',
        'not null' => TRUE,
        'size' => 'big',
      ),
      'expire' => array(
        'description' => 'The time since Unix epoch in seconds when this item expires. Defaults to the maximum possible time.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 2147483647,
      ),
    ),
    'primary key' => array('collection', 'name'),
    'indexes' => array(
      'all' => array('name', 'collection', 'expire'),
      'expire' => array('expire'),
    ),
  );

  $schema['sequences'] = array(
    'description' => 'Stores IDs.',
    'fields' => array(
      'value' => array(
        'description' => 'The value of the sequence.',
        'type' => 'serial',
        'unsigned' => TRUE,
        'not null' => TRUE,
      ),
    ),
    'primary key' => array('value'),
  );

  $schema['sessions'] = array(
    'description' => "Drupal's session handlers read and write into the sessions table. Each record represents a user session, either anonymous or authenticated.",
    'fields' => array(
      'uid' => array(
        'description' => 'The {users}.uid corresponding to a session, or 0 for anonymous user.',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
      ),
      'sid' => array(
        'description' => "A session ID (hashed). The value is generated by Drupal's session handlers.",
        'type' => 'varchar_ascii',
        'length' => 128,
        'not null' => TRUE,
      ),
      'hostname' => array(
        'description' => 'The IP address that last used this session ID (sid).',
        'type' => 'varchar_ascii',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'timestamp' => array(
        'description' => 'The Unix timestamp when this session last requested a page. Old records are purged by PHP automatically.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'session' => array(
        'description' => 'The serialized contents of $_SESSION, an array of name/value pairs that persists across page requests by this session ID. Drupal loads $_SESSION from here at the start of each request and saves it at the end.',
        'type' => 'blob',
        'not null' => FALSE,
        'size' => 'big',
      ),
    ),
    'primary key' => array(
      'sid',
    ),
    'indexes' => array(
      'timestamp' => array('timestamp'),
      'uid' => array('uid'),
    ),
    'foreign keys' => array(
      'session_user' => array(
        'table' => 'users',
        'columns' => array('uid' => 'uid'),
      ),
    ),
  );

  // Create the url_alias table. The alias_storage service can auto-create its
  // table, but this relies on exceptions being thrown. These exceptions will be
  // thrown every request until an alias is created.
  $schema['url_alias'] = AliasStorage::schemaDefinition();

  return $schema;
}