"Entity Not Mapped" exception when using HQL. Works with Criteria.

Question

Before talking about the problem here's some background:

1. There are 3 assemblies.
   1. One containing an Entity class and the problem HQL.
   2. Tests.
   3. Website.
2. All the tests in the Tests assembly for are passing for the HQL.
3. The exception is thrown in the website.
4. If I use the equivalent Criteria code it works fine in all assemblies calling it.

Onto the problem. When calling the following HQL

var commentCount = 
    session.CreateQuery("select e.CommentCount from Entity e where e.Id = :entityId")
    .SetParameter("entityId", string.Format("{0}:{1}", entityType, entityId))
    .UniqueResult<int>();

this exception is thrown:

Entity is not mapped [select e.CommentCount from Entity e where e.Id = :entityId]

As mentioned I can just change to using Criteria, but I'm worried there might be an underlying problem that the use of Criteria is covering up.

Any ideas? Thanks.

Answer 1

Use C#'s own as string :

var commentCount =  session.CreateQuery("select e.CommentCount from Entity e where e.Id = :entityId and rownum <= 1")
                           .SetParameter("entityId", string.Format("{0}:{1}", entityType, entityId))
                           .UniqueResult() as string;

Do note that you might have to add the and rownum <= 1 clause at the end.

Answer 2

I forgot to add the assembly to my hibernate-configuration!

Here's the code:

<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
    <session-factory name="demo">
        <mapping assembly="Users" />
    </session-factory>
</hibernate-configuration>

I'm not sure why criteria worked. I'm guessing it has something to do with the type being explicitly defined.

Answer 3

Add auto-import="true" to your hibernate-mapping elements. That should take care of it.