named queries can be defined only on an entity - problem

[olze oli]

hi there,

i have a new problem.
i have a domain object called "Lecture", and in the database its called "Lectures"
i want to use hibernate to manage this database stuff so i created the annotations:

 @Entity
@Table(name = "Lectures", catalog = "MontyBrogan", schema = "")
@NamedQueries({@NamedQuery(name = "Lectures.findAll", query = "SELECT l FROM Lectures l"), @NamedQuery(name = "Lectures.findById", query = "SELECT l FROM Lectures l WHERE l.id = :id")})
public class Lecture implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "ID", nullable = false)
    private Integer id;
    @Basic(optional = false)
    @Lob
    @Column(name = "Desc", nullable = false, length = 65535)
    private String desc; ... much more code ...   

the interpreter says:
named queries can be defined only on an entity or a mappedsuperclass class.
i have no idea whats the problem because with @entity i tell hibernate that its a entity, dont i?

ps.: and yes, i used the netbeans "do the magic"-create objects from database sheme ;)

[Rachel Swailes]

Hi there

I think that in this case you need to refer to Lecture in your named queries as Lecture because that is the name of the class. You never need to refer to the name of the table anywhere in your code (HQL included) with the exception of the @Table annotation or if you ever do plain sql queries (that is without hibernate).

Try changing your named queries to use the name of the class instead of the name of the table and see if that works.

Cheers,
Rachel

[olze oli]

Hi Rachel,

thats what i tried first ;)
And no, it doesnt resolve the problem.
What's funny, everything works fine... as far as i can say (because the portlet is not finished yet).

Btw. i changed the database fields (from plural to singular) - imo it looks ugly now, but its working...

Any other ideas what could be the problem?

[Rachel Swailes]

Hmm, I'm interested to find out why this is. I'm busy putting an example together so that I can see what Hibernate does.

At what point do you get the error?

[olze oli]

Netbeans only shows the error message.
If you'd like to i give you all the code + database layout

[Rachel Swailes]

Thanks for the offer but I think I'll try further with a simple setup and see what I can find. I've put it together in IntelliJ and it's not showing any error messages so I'm going to try reading and writing some data with the queries and see how far I get.

[Rachel Swailes]

I set it up to store, retrieve and delete some lectures using the named query annotation that you had pasted above.

When running the code as is I got these errors

[ERROR] Error in named query: Lectures.findById
org.hibernate.hql.ast.QuerySyntaxException: Lectures is not mapped [SELECT l FROM Lectures l WHERE l.id = :id]

ERROR] Error in named query: Lectures.findAll
org.hibernate.hql.ast.QuerySyntaxException: Lectures is not mapped [SELECT l FROM Lectures l]

Initial SessionFactory creation failed.org.hibernate.HibernateException: Errors in named queries: Lectures.findById, Lectures.findAll
 

Then I changed one of the queries to use Lecture instead of Lectures and got an error on the other named query

 org.hibernate.hql.ast.QuerySyntaxException: Lectures is not mapped [SELECT l FROM Lectures l WHERE l.id = :id]
Initial SessionFactory creation failed.org.hibernate.HibernateException: Errors in named queries: Lectures.findById

and when I changed them both to be Lecture instead of Lectures there was no error.

So in the end the head of Lecture looked like this

 @Entity
@Table(name = "Lectures")
@NamedQueries({@NamedQuery(name = "Lecture.findAll", query = "SELECT l FROM Lecture l"), @NamedQuery(name = "Lecture.findById", query = "SELECT l FROM Lecture l WHERE l.id = :id")})
public class Lecture {
 

Are you able to run your code at all or does the error from Netbeans prevent you from compiling and running it?

[olze oli]

no i can compile and run the portlet fine (no it doesnt run fine, but thats because im absolutly new to hibernate, spring and struts)
the output of the sql querys looks also ok, like:

 Hibernate: select lecture0_.ID as ID5_, lecture0_.Desc as Desc5_, lecture0_.ID_Prof as ID3_5_ from MontyBrogan.Lecture lecture0_
Hibernate: select user0_.ID as ID4_1_, user0_.email as email4_1_, user0_.firstname as firstname4_1_, user0_.isAdmin as isAdmin4_1_, user0_.isProf as isProf4_1_, user0_.lastname as lastname4_1_, user0_.password as password4_1_, student1_.ID as ID3_0_, student1_.MatrNr as MatrNr3_0_ from MontyBrogan.User user0_ left outer join MontyBrogan.Student student1_ on user0_.ID=student1_.ID where user0_.ID=?
   

if you need further informations, just reply
maybe its just a netbeans bug?

[Rachel Swailes]

If it's generating the right sql for you then I think I'd be looking at if it's a problem with netbeans. I did a quick search and found this at Stack Overflow.