NHibernate.MappingException: Unknown entity class

65 Responses to “NHibernate.MappingException: Unknown entity class”

1. 

   Olavo Alexandrino July 19, 2007 at 8:07 pm #

   Thanks a lot by your post!

   Was a shame discover that!
   

   Reply
2. 

   Jam July 21, 2007 at 5:50 pm #

   Exactly what I suffered! Thanks man u rule!

   Reply
3. 

   Ben August 3, 2007 at 2:09 pm #

   Maybe I am a little slow. I have the same issue but, I am unable to get this working even when I include the changes you discuss above. I am referencing the App_Code directory without any success. Can anyone be more specific about referencing components in the App_Code folder? Any assistance is greatly appreciated.

   Reply
4. 

   koresh September 17, 2007 at 3:03 am #

   Hi from Russia!)
   I specified the Assembly name of “App_Code” but i have this issue again…
   this is my .hbm.xml

   in web.congig i set up

   Reply
5. 

   Jason September 17, 2007 at 12:14 pm #

   Hey Ben & Koresh – One thing that I did when I was having some similar problems was create a little bit of debug code to print out the assembly name of one of my classes in question so i could see what it was. There is a method to do that somewhere in the Reflection class, sorry I don’t remember off the top of my head.

   Reply
6. 

   Rui October 13, 2007 at 1:44 pm #

   Try to add the following line in configuration file inside the (session-factory) tab:

   (mapping resource=”namespace/hbm.xml file” assembly=”namespace” /)

   Example:

   (mapping resource=”Quickstart.Cat.hbm.xml” assembly=”Quickstart” /)

   Replace the () by the correct character because this blog doesnt accept those

   Reply
7. 

   Ronald October 25, 2007 at 6:16 am #

   Hi from South Africa.

   I have the same problem, but not with ASP.net. I am using a normal application. does anyone know what to do here?

   Ronald

   Reply
8. 

   Meziano October 25, 2007 at 8:02 am #

   Hey all,
   the 2 Hibernate Mappingfiles properties: ‘Buildvorgang’ and ‘In ausgabeverzeichnis kopieren’ (sorry I have a German VS, the 2 & 3 properties) must be set of ‘Eingebetete Ressource’ and ‘immer kopieren’.
   That’s it!

   Reply
9. 

   Jason October 28, 2007 at 5:50 pm #

   Hey Ronald – with a normal application it most likely is the same thing where the assembly name is not right or else you don’t have the mapping files set to be “embedded resource” – try to use the reflection classes or the debugger to figure out what the assembly name is for your objects that you are trying to map.

   Reply
10. 

    Alexandre November 26, 2007 at 3:37 pm #

    Thanks man! I’m just starting with NHibernate on VS2005. I worked just embedding the XML file.

    Reply
11. 

    Paul March 9, 2008 at 5:36 pm #

    In visual studio 2005 how do you embed the resource the property panel only gives file name and full path as the two properties for my xml file, im hunting high and low to find this for VS 2005.

    Reply
12. 

    frc March 11, 2008 at 9:21 am #

    Try naming the namespace of the project you’re using different as the NHibernate or at least the property of the assembly name to be different. After that set class props to virtual. Hope that makes sense. Worked here! Cheers!
    P.S. Embeded resource needed also on the xml mapped file

    Reply
13. 

    Avinash Joshi March 11, 2008 at 10:48 pm #

    thanks My friend you help a Lot

    Reply
14. 

    Michael Hale March 24, 2008 at 1:52 pm #

    Another reason for the Unknown entity class error is when you have the same property defined in 2 different ways in your hbm file. It seems like this should give you a different type of error.

    Reply
15. 

    JWB March 26, 2008 at 3:11 am #

    And check that your file is correctly named .hbm.xml

    Reply
16. 

    Tim Ivashchenko March 29, 2008 at 5:40 am #

    Thanks! Your explanation resolved my problem. Good luck!

    Reply
17. 

    Daniel April 10, 2008 at 11:54 am #

    Thank you so much !!!
    Almoust a whole day trying to find out why it wasn’t working !
    Two minutes on your web site and I found the solution !

    Reply
18. 

    Lee April 22, 2008 at 6:49 pm #

    Thanks for posting this. I ran into the same problem – in addition to the fix you outlined, I also had to add
    (mapping assembly=”my_assembly_name”/) to get this to work.

    Reply
19. 

    Tomas May 5, 2008 at 3:06 am #

    Thanks! This solved my problem.

    Reply
20. 

    Kalpesh May 9, 2008 at 8:27 am #

    Hey ..u made my day..

    Reply
21. 

    Jesús Miasnikoff May 28, 2008 at 7:19 pm #

    excelent!

    Reply
22. 

    Vignesh May 30, 2008 at 6:38 am #

    Hey !! I have also done a sample in Hibernate ASP.Net application. Its working perfectly. Just make sure the XML file build property is set to ‘Embedded Resource’.

    Reply
23. 

    Vignesh May 30, 2008 at 6:39 am #

    I will try to explore further about the DB insertions, updations etc and sahre it with you guys. If any of you guys have any idea on inserting identity values etc.. please let me know !! Thanks and Happy coding !!!

    Reply
24. 

    Sandesh Deshmukh June 13, 2008 at 1:27 am #

    Thanks a lot bro, this is such a stupid mistake, but one of the most difficult ones to figure out!

    Reply
25. 

    Honda July 2, 2008 at 3:32 am #

    Thank you!!!!!!!

    Reply
26. 

    Prachi July 2, 2008 at 11:04 am #

    I am having a similar problem.Can anyone please tell me where in the web.config file I am supposed to add the line??It is not recongnizing the setting…Please reply..thanks a lot in advance

    Reply
27. 

    Chad July 10, 2008 at 4:06 am #

    Thanks dude. I obviously didn’t read the tuturials closely enough to notice the ‘Embedded Resource’ setting!

    Reply
28. 

    Naveen July 30, 2008 at 2:18 pm #

    Hi,

    There could be one more issue if you are not fetching the configuration properly. Below should be the sequence of the statements:

    // Fetch the configuration
    NHibernate.Cfg.Configuration config;
    config = new NHibernate.Cfg.Configuration().Configure();

    // Load the assembly
    config.AddAssembly(“Model”);
    private static ISessionFactory sessionFactory = config.BuildSessionFactory();

    // DEBUG – check count to verify whether all classes are loaded properly
    IDictionary colls = sessionFactory.GetAllClassMetadata();
    int count = colls.Count;

    Reply
29. 

    Alejandro September 3, 2008 at 11:01 am #

    Thanks!!

    From Argentina.

    Reply
30. 

    Solmaz September 17, 2008 at 4:51 am #

    vaooooooooooooo, tanx very much , I spent 4 hour for that and u save me

    Reply
31. 

    Dharmbir September 23, 2008 at 7:04 am #

    Hi,
    I am also facing the same problem and I have added all the seeting that you guys have suggested but still it’s giving me the same error “Could not find the dialect in the configuration”

    Reply
32. 

    Dharmbir September 23, 2008 at 7:05 am #

    Hi,
    please see my app.config file
    (nhibernate)
    (add key=”hibernate.show_sql”
    value=”false” /)
    (add key=”hibernate.connection.provider” value=”NHibernate.Connection.DriverConnectionProvider” /)
    (add key=”hibernate.dialect” value=”NHibernate.hibernate.Dialect.MsSql2000Dialect” /)
    (add key=”hibernate.connection.driver_class” value=”NHibernate.Driver.SqlClientDriver” /)
    (add key=”hibernate.connection.connection_string” value=”Data Source=sqldev;Initial Catalog=AssetIceTest;IntegratedSecurity=SSPI;” /)
    (mapping resource=”Employee.hbm.xml” assembly=”MyClass” /)

    Reply
33. 

    Sagar September 25, 2008 at 7:49 am #

    I’m unable to resolve this issue.. Can anyone please help? I’ve set the “Build Action” to “Embedded Resource and secondly I’ve added the below line in my config file:

    User.hbm.xml is my hbm.xml file and the name my application is NHibernate.

    Thanks in advance

    Reply
34. 

    Jason September 25, 2008 at 11:13 am #

    Hey Sagar, not too sure if your project being named NHibernate is a possible problem due to namespace collision..? It’s tough to say, but again, the error is always due to NHibernate not being able to locate your class. So, check your folder paths, assembly name and everything.

    Also, possibly grab the source of NHibernate and put a debugger on it to see what class it is trying to find.

    Reply
35. 

    Jason September 25, 2008 at 11:15 am #

    Hey Dharmbir, I don’t think this is the same problem. The error about the Dialect seems to me to indicate a problem with your configuration of the DB type. I haven’t encountered that one yet, but I would be looking into the dialect configuration and database connection settings.

    Reply
36. 

    Solmaz September 27, 2008 at 1:32 am #

    Tanx alot, i have a problem and ur solution solved it

    Reply
37. 

    Chris Needham November 24, 2008 at 4:48 am #

    Thanks fella!

    Reply
38. 

    Love November 30, 2008 at 9:37 am #

    Thanks mr. programmer.

    Reply
39. 

    darnok December 31, 2008 at 11:35 am #

    Thanks from Poland for “Embeded Resource” tip

    Reply
40. 

    Vivek March 20, 2009 at 6:26 am #

    Thanks a lot… this post helped me

    Reply
41. 

    Jesus April 30, 2009 at 12:31 am #

    thanks a lot man I suffered by that exception
    3 hours:D(JESUS CHRIST)

    Reply
42. 

    Daniel May 15, 2009 at 6:33 am #

    Thanks man, sometimes the you just forget to set the embedded ressource…

    Reply
43. 

    yogesh May 26, 2009 at 1:36 am #

    hello, i m using asp.net website
    can u tell me how to set build property in asp.net website application…..
    i could not found the build property of xml file here….so please

    Reply
44. 

    mahdi June 4, 2009 at 5:45 am #

    realy thank u?

    Reply
45. 

    asif June 13, 2009 at 4:25 am #

    A0A
    plz update me how i can
    “Build Action” to “Embedded Resource.
    i m using asp.net 2.0 and i have placed the the code in App_Code folder.
    i m getting unknow entity Cat class.

    Reply
46. 

    mehdi July 2, 2009 at 10:41 pm #

    Thank you

    Reply
47. 

    gash July 30, 2009 at 2:04 pm #

    Thanks a lot. It didn’t exactly solve my problem but gave me an idea for the solution. I had to ensure that there were no mis-spellings in my mapping files.

    Reply
48. 

    Suman September 4, 2009 at 5:19 am #

    Hi,

    I am new to nhibernet. I have created on Console Application and added User Class and corresponding hbm.xml made it embeded resource

    Code

    Configuration cfg = new Configuration();
    cfg.Configure(@”ProjectLocation\hibernate.cfg.xml”);

    it is giving
    NHibernate.MappingException: Could not compile the mapping document: POCNibernet.User.hbm.xml

    Reply
49. 

    John R December 3, 2009 at 12:21 pm #

    You just solved my problem! A class that was not recognized in my NHibernate mapping was not set to “Embedded Resource”. Changing that setting fixed my bug. Thanks a bunch!

    Reply
50. 

    Juan P March 17, 2010 at 10:30 am #

    Hi from Mexico!
    Thank you so much!!

    Reply
51. 

    peter March 17, 2010 at 3:45 pm #

    in web.config

    did it for me

    thanks for this blog

    Reply
52. 

    Dedeco May 12, 2010 at 9:16 pm #

    Thanks a lot!! Works for me “set to “Embeded Resource.””.

    Reply
53. 

    Mugabi September 12, 2010 at 9:52 pm #

    Tks GENIO!!!!!

    Reply
54. 

    Mohsin October 1, 2010 at 12:30 am #

    Thanks man !!!

    Reply
55. 

    vijay chinatal November 25, 2010 at 5:27 am #

    thanks a lot

    Reply
    • 

      sekhar February 15, 2011 at 5:23 am #

      Thanx man

      Reply
56. 

    fararz March 24, 2011 at 2:48 am #

    wah wah .. .. thanks alot

    Reply
57. 

    Siriquelle March 24, 2011 at 7:52 am #

    Thanks

    Reply
58. 

    Mahesh October 20, 2011 at 4:51 am #

    Thanks a lot…..

    Reply
59. 

    Pava January 2, 2012 at 4:59 am #

    Thanks,Guys I have faced the same problem but my mistake was incorrect file name.
    I have typed user,nbm.xml insterad of user.hbm.xml.

    Cheers..

    Reply
60. 

    sam January 27, 2012 at 4:20 am #

    thanks alot

    Reply
61. 

    Taha February 29, 2012 at 5:03 am #

    I am getting the error when the iSession.save(“[className]“) method runs
    Please help

    Reply
62. 

    Stone March 21, 2012 at 6:13 am #

    And check that your file is correctly named .hbm.xml
    <== YOu saved my life!!!

    Reply
63. 

    Pradeep April 16, 2012 at 6:05 am #

    superb..nice solution..just we need to add in configuration file…

    Reply

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