Schema::mapKeyDefinition

protected Schema::mapKeyDefinition(array $key_definition, array $mapping)

protected function mapKeyDefinition(array $key_definition, array $mapping) {
  foreach ($key_definition as &$field) {
    // The key definition can be an array($field, $length).
    if (is_array($field)) {
      $field = &$field[0];
    }
    if (isset($mapping[$field])) {
      $field = $mapping[$field];
    }
  }
  return $key_definition;
}