public function toFieldDefinition(StorageFieldDefinition $storageDef, FieldDefinition $fieldDef)
{
$fieldDef->fieldTypeConstraints->fieldSettings = new FieldSettings(array('isISBN13' => !empty($storageDef->dataInt1) ? (bool) $storageDef->dataInt1 : true));
$fieldDef->defaultValue->data = $storageDef->dataText1 ?: null;
$fieldDef->defaultValue->sortKey = $storageDef->dataText1 ?: '';
}