anchor.diff:  ----
   return SqlClientHelper.inTransactionUni(client, tx -> tx
   
  -        .preparedQuery("INSERT INTO person (firstname,lastname) VALUES ($1,$2) RETURNING (id)")
  +        .preparedQuery("INSERT INTO person (firstname,lastname) VALUES ($1,$2) RETURNING id")
                   .execute(Tuple.of(person.getFirstName(), person.getLastName()))
   
           .onItem().transformToUni(id -> tx.preparedQuery("INSERT INTO addr (person_id,addrline1) VALUES ($1,$2)")
  
positive.code: .src/main/java/org/acme/vertx/Fruit.java
  ----
  public Uni<Long> save(PgPool client) {
      return client.preparedQuery("INSERT INTO fruits (name) VALUES ($1) RETURNING (id)").execute(Tuple.of(name))
              .onItem().transform(pgRowSet -> pgRowSet.iterator().next().getLong("id"));
  }
  ----
  
negative.code: ----
  public static Uni<Void> insertTwoFruits(PgPool client, Fruit fruit1, Fruit fruit2) {
      return SqlClientHelper.inTransactionUni(client, tx -> {
          Uni<RowSet<Row>> insertOne = tx.preparedQuery("INSERT INTO fruits (name) VALUES ($1) RETURNING id")
                  .execute(Tuple.of(fruit1.name));
          Uni<RowSet<Row>> insertTwo = tx.preparedQuery("INSERT INTO fruits (name) VALUES ($1) RETURNING id")
                  .execute(Tuple.of(fruit2.name));
  
          return insertOne.and(insertTwo)
  