hibernate
Unexpected database connection problem. Hibernate broken pipe.
While using Hibernate, several times I faced the same database communication problem: for some reason after long inactivity time connection was closed. Each time that happens it takes some my time to remember the solution. So this post is more like a note for myself, but also can be helpful for those who can find it in Internet.
Hibernate. Count queries without HQL
I like to use Criteria class for making database queries. Its easy to use and easy to understand, much better then HQL queries. For example:
@SuppressWarnings("unchecked")
public List<LogAdd> findAddLogs(Long minLogID) {
Criteria criteria = session.createCriteria(LogAdd.class);
criteria.add(Restrictions.gt("id", minLogID));
criteria.addOrder(Order.asc("date"));
return criteria.list();
}
Previously I had to use HQL only for writing 'count' type queries. Because just trying to get collection size mean to load all elements into memory from database and only then count them. Of course such kind of code isn't acceptable.