I'm curious about the advantages/disavantages of using sql vs. hql with hibernate 3.1. With SQL, we save the learning curve, but what are losing out on that hql does? With hql, I know I can concentrate on my object, but am I losing anything with performance? I'm not looking to be talked into either one, just looking to make an objective list of pros/cons that I can make a decision from.

Thanks.

Are you wanting to use SQL through Hibernate or via a raw JDBC connection provided through Hibernate? If the former, Hibernate can still map your objects to the tables and cols, for instance from the docs:

List cats = session.createSQLQuery(
"SELECT {cat.*} FROM CAT {cat} WHERE ROWNUM<10",
"cat",
Cat.class
).list();

The latter does provide a big con in that you are tied to a database implementation. Should a table or column get renamed, then you would have to change every SQL statement that uses it. Also, if you use SQL syntax specific to a db server, changes would have to be made should the database be moved to a new server.

The biggest advantage for HQL to me is not being tied to a particular database. I find it easier to change an XML file than to search through a bunch of Java code. This is also why I don't use annotations as that will tie your POJO to a particular implementation, thereby defeating the whole purpose of a POJO for data.

I do not think the parsing of hql to sql will result in any noticable performance delay.

I've found there are no negative sides to writing anything in hql. HQL is so similar to sql that there is virtually nothing to learn to get the hang of it. It is less verbose, database independent, and being able to work with objects/attributes makes it very easy to use.