anchor.diff:  keep the existing constraints and create the missing one.
   Default value is `DROP_RECREATE_QUIETLY`.
   
  -[WARNING]
  -====
  -At the moment, you must not specify the property `hibernate.transaction.jta.platform` when using Neo4j.
  -It would override Hibernate OGM's version and the transactions would not work correctly.
  -====
  -
  -[NOTE]
  -====
  -Use the following method to retrieve the transaction manager
  -(it needs to be done after the `EntityManagerFactory` has been bootstrapped):
  -
  -[source, JAVA]
  -----
  -private static TransactionManager extractJBossTransactionManager(EntityManagerFactory factory) {
  -    SessionFactoryImplementor sessionFactory =
  -        (SessionFactoryImplementor) ( (HibernateEntityManagerFactory) factory ).getSessionFactory();
  -    return sessionFactory.getServiceRegistry().getService( JtaPlatform.class ).retrieveTransactionManager();
  -}
  -----
  -====
  -
   [NOTE]
   ====
   When bootstrapping a session factory or entity manager factory programmatically,
  
positive.code: tx.commit();
  ----
  ====
  
  [[ogm-neo4j-queries]]
  === Queries
  
negative.code: [[ogm-neo4j-transactions]]
  === Transactions
  
  In Neo4j, operations must be executed inside a transaction.
  Make sure your interactions with Hibernate OGM are within a transaction when you target Neo4J.
  
  .Example of starting and committing transactions
  ====
  