Proper practice to check table then save / update for Hibernate

Question

All applications using hibernate need save and update to interact with the database. For save, I will check the existence for some criteria. If it doesn't exist, I will save. For update, I will check the existence and certain criteria to determine whether update or not. What is the best practice to do the check and save / update?

I am currently creating a separate function that open a session and search to determine the existence. The session open/close is very clumsy. I think there should be better way to do it.

public Event searchByDateAddress(Date _date, String _address, boolean _closeSess)
{
    try
    {
        if(!session.isOpen())
        {
            session = HibernateUtil.getSessionFactory().openSession();
        }
        session.beginTransaction();
        Criteria criteria = session.createCriteria(Event.class);
        criteria.add(Restrictions.eq("date", _date));
        criteria.add(Restrictions.eq("address", _address));
        criteria.setFetchMode("organizerProfile", FetchMode.JOIN);
        Event evt = (Event)criteria.uniqueResult();
        if(_closeSess)
        {
            session.close();
        }
        if (evt==null)
        {
            LogUtils.logInfo("The event does not exist: " + _date + " " + _address);
            return null;
        }
        else
        {
            return evt;
        }
    }
    catch(Exception e)
    {
        LogUtils.logInfo(e.toString());
        if(_closeSess)
        {
            session.close();
        }
        return null;
    }
}


public EventDTO insertEvent(Event _event)
{
    try
    {
        Event tmpEvent=new Event();
        //Event not exists
        if((tmpEvent=this.searchByDateAddress(_event.getDate(), _event.getAddress(), true))==null)
        {
            //insert
            if(!session.isOpen())
            {
                session = HibernateUtil.getSessionFactory().openSession();
            }
            Transaction tx=session.beginTransaction();
            long retOid=(Long)session.save(_event);
            session.flush();
            tx.commit();
            session.close();
            _event.setOid(retOid);
            return new EventDTO(_event);
        }
    }
    catch(Exception e)
    {
        e.printStackTrace();
        session.close();
    }
    return new EventDTO();
}

Thanks

score 0 · Answer 1 · answered Mar 17 '20 at 09:05

Regarding session handling, its best to handle in the API level, a leve before this "EventService". So you always assume that the session is available in the service methods. Then the code will look more neet, avoiding session with the hibernate query.

Its also possible to avoid session handling at all using @Transactional attribute in the methods where you want session. This is possible using Spring. Look at : https://spring.io/guides/gs/managing-transactions/ for more info.

For checking for if a table has the data you with your where clause you may use count(*). So you dont need to get all the data at first.

Look at this example: hibernate native query, count

Proper practice to check table then save / update for Hibernate

1 Answers1