In the following query, "key" is a variable in the class Cats.

Why does this query work when embedded in a java class?
Query q = session.createQuery("from Cats where " + key + " = :value");

But not in a named query like this?
<query name="select_all_cats"><![CDATA[from cats where key = :value]]></query>

When I echo the HQL query that gets generated from both, the queries print out identical, yet when I try to run from a named query, I get no results. Both styles of query are picking up the value of "key" correctly and I know this because I can see it in the HQL that is echoed to the console.

Help! I would really like to get this query running from a named query!

for the createQuery example, what are you passing as the value for the var 'key' ; how are you calling the named query in your application?

the value of "key" is the name of a column name in the database table "cats" which maps to the java class Cats.

the query is called like this:

Query q = session.getNamedQuery("select_all_cats");

take a look at http://www.hibernate.org/hib_docs/v3/re ... ting-named .

you need to bind a value to the 'value' parameter. it also looks as though you are only trying to query for a property of Cats called 'key' .

hql is case sensitive, to your going to decide on "cats" or "Cats".

I do set the value of "value" in the source code with:

q.setParameter("value", value);

And I know it is converting the "key" variable to the column name "id" because I can see it in the hibernate query string when I echo to the console.

This is the complete text of my hibernate in source code:

Session session = HibernateUtil.currentSession();
Transaction tx = session.beginTransaction();
Query q = session.getNamedQuery("select_all_cats"); q.setParameter("value", value);
List result = q.list();
HibernateUtil.sessionFactory.close();

I know my case usage is correct. The table name is cats and the class name is Cats.

I just ran the named query again and it is true, it isn't substituting the value for "key" like I thought. Why them does it substute it correctly with an embedded createQuery statement like above but not in the named query? Am I limited to using createQuery statements when I need to use variables for column names? If so, then this limits my ability to use named queries and this is icky.

there is no substitution in the createQuery case , your literally putting the property name in the query. i don't know if you can substitute values for property/columns, but we will both know after you try ;)

if that doesn't work, try a filter. http://www.hibernate.org/hib_docs/v3/re ... te-filters

icky ? ;)

thanks for all your help and inputs Denise!

icky -- well, I just couldn't think of anything else to say. I'm tired of battling this one :-)

I know one thing for sure, if it can't be done, then we need to have Hibernate enhanced with a new method like setParameter that will set the value of a column variable. Let's call it setColumn. As a matter of fact, as much as I hate to modify third party source code, I think I'll do it!

Thanks again!

Have you looked at the Criteria interface? (http://www.hibernate.org/hib_docs/v3/reference/en/html_single/#querycriteria)

If you are trying to change which column you are using in a query, you probably want to look at using Criteria instead of named queries. It allows you to basically build queries dynamically.

The substitution you talk about in the embedded createQuery statement is merely Java String concatenation, not some magical Hibernate behavior.

Oh yes Preston, I can see that clearly now. Amazing what a little sleep will do!
Nathan, I considered criteria queries but I was hesitant to put more time into it to learn about them but it looks like I have to. I was looking for a quick way to make it work.

Well, like I said, a little sleep (and a lot of coffee) and the Criteria query worked great!!

Thanks everyone for your inputs!

This is a great forum. It really works!