public OUser create() {
acquireExclusiveLock();
try {
if (getDatabase().getMetadata().getSchema().getClasses().size() > 0)
throw new OSecurityException("Default users and roles already installed");
// CREATE ROLE AND USER SCHEMA CLASSES
final OClass roleClass = getDatabase().getMetadata().getSchema().createClass("ORole");
roleClass.createProperty("mode", OType.BYTE);
roleClass.createProperty("rules", OType.EMBEDDEDMAP, OType.BYTE);