My Presentation at OKCodeCamp - DDD with NHibernate

cheers!

I thought it was a great presentation. What was the software that you mentioned to help with creating the NHibernate mapping files?

It's called ActiveWriter and it generates the ActiveRecord model objects for use with that pattern. There are probably some more tools out there, but I recommend just digging in so that you really understand what's going on when you choose different settings in the mapping. Generating the schema directly from the mapping is a great way to do this.

Here's the link to the ActiveWriter project:
http://www.altinoren.com/activewriter/

Hi Ben, can you share the database files that are use in your demo? It will be handy. I am picking up nhibernate.

The database will get created automatically. Read the last line of the post.

Oh that simple. Alright will give it a try. Thanks.

Hi, I had a problem here.

I changed the app.config file as below:

<add key="hibernate.connection.provider" value="NHibernate.Connection.DriverConnectionProvider"/>
<add key="hibernate.dialect" value="NHibernate.Dialect.MsSql2005Dialect" />
<add key="hibernate.connection.driver_class" value="NHibernate.Driver.SqlClientDriver" />
<add key="hibernate.connection.connection_string" value="Server=WENCHINGPC\SQL2005;initial catalog=NHibernateDemo;Integrated Security=SSPI" />

So I created the NHibernateDemo database in SQL Server 2005 Developer Edition.

Then I try to run the HelloWorld application, I got this error.

could not load an entity: [HelloWorld.Message#7][SQL: SELECT message0_.Id as Id0_1_, message0_.Text as Text0_1_, message0_.nextMessage_id as nextMess3_0_1_, message1_.Id as Id0_0_, message1_.Text as Text0_0_, message1_.nextMessage_id as nextMess3_0_0_ FROM Messages message0_ left outer join Messages message1_ on message0_.nextMessage_id=message1_.Id WHERE message0_.Id=?]

I also tried on removing that NHibernateDemo database. No difference though.

Any help :)

Thanks.

It looks like the database was built successfully, can you paste the inner exception? That should tell us what's going wrong.

InnerException (from debug) - {"Invalid object name 'Messages'."}

The full details of exception:

NHibernate.ADOException was unhandled
Message="could not load an entity: [HelloWorld.Message#7][SQL: SELECT message0_.Id as Id0_1_, message0_.Text as Text0_1_, message0_.nextMessage_id as nextMess3_0_1_, message1_.Id as Id0_0_, message1_.Text as Text0_0_, message1_.nextMessage_id as nextMess3_0_0_ FROM Messages message0_ left outer join Messages message1_ on message0_.nextMessage_id=message1_.Id WHERE message0_.Id=?]"
Source="NHibernate"
StackTrace:
at NHibernate.Loader.Loader.LoadEntity(ISessionImplementor session, Object id, IType identifierType, Object optionalObject, Type optionalEntityName, Object optionalIdentifier, IEntityPersister persister)
at NHibernate.Loader.Entity.AbstractEntityLoader.Load(ISessionImplementor session, Object id, Object optionalObject, Object optionalId)
at NHibernate.Loader.Entity.AbstractEntityLoader.Load(Object id, Object optionalObject, ISessionImplementor session)
at NHibernate.Persister.Entity.AbstractEntityPersister.Load(Object id, Object optionalObject, LockMode lockMode, ISessionImplementor session)
at NHibernate.Impl.SessionImpl.DoLoad(Type theClass, Object id, Object optionalObject, LockMode lockMode, Boolean checkDeleted)
at NHibernate.Impl.SessionImpl.DoLoadByClass(Type clazz, Object id, Boolean checkDeleted, Boolean allowProxyCreation)
at NHibernate.Impl.SessionImpl.Get(Type clazz, Object id)
at NHibernate.Impl.SessionImpl.Get[T](Object id)
at HelloWorld.Program.Main(String[] args) in C:\Documents and Settings\Administrator\Desktop\NHiibernate\Sept 17\ddd_20with_20nhibernate\ddd with nhibernate\demos\01.hello.world\HelloWorld\Program.cs:line 32
at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

Can you look in the setup method of one of those tests... the one where it uses the SchemaExport object to build the database. Run that line using the debugger, then click stop.

You should be able to see the database if the connection string is pointing to a valid sql 2000/2005 server.

Do you have a database? if so, please list the tables and columns here.

Thanks for the response.

You mention earlier "The database will get created automatically. Read the last line of the post.". Yes I have a database called NHibernateDemo, but it is empty. Do I have to creates tables manually? Maybe I didn't get your meaning right. Can you clarify?

Take note, I am looking at the HelloWorld demo. I don't see any test? I cannot see any SchemaExport from the HelloWorld example. Hmm.. am i looking at the right file? Coz I downloaded it from the link attached in this email.

From this code from HelloWorld,

using(ISession session = _factory.OpenSession())
{
Message msg = session.Get<Message>(7);
DisplayMessage(msg);

msg.NextMessage = new Message("I'm attached.");


session.Flush();
}

I debug on the _factory.OpenSession(), and when i step in.. I can see that the session is on the right SQL Server 2005 database and the state is open.

Thanks :)

I thought I had built that database. I think you're right. I'm sorry!

Create a table called Messages with the following columns:

ID int (PK, Identity)
Text varchar(255) not null,
nextMessage_id int null

That should work.

Thanks for your reply. Appreciate this. Cool I will work on that Database for HelloWorld now.

How about the other examples like DDD, Blog and Restraurant Systems?

How do I create those database tables too? Is it alright if you can generate some script so I can download it? Easier :P

Any help?