Hi,

I've another problem...wanted to create a session helper, which should store ISessionFactory by calling one time only. I've declared static variables holding the Assembly name and ISessioniFactory info etc. But it seems not the case.

I use the following lines to invoke and get a session. If I didn't call the setAssembly function, it will have error stating that no assembly name defined. But as mentioned, the assembly name should have been stored after called once when program starts up, the result is unexpected to me.:

NHibernateSessionHelper.setAssembly("MyAppl.Business");
sess = NHibernateSessionHelper.openSessionFactory().OpenSession();

Learned from the forum that building Session Factory is resources-intensive. That's the reason I wanted to have Session Factory invoked once for the whole application run-time. Pls point me out which part I should remedy to have the info stored and desired. Thanks Again!

The Helper code:

public class NHibernateSessionHelper
{
private static string _assembly;
private static Configuration _cfg;
private static ISessionFactory _sf;
private static ISession _sess;

public static Configuration openConfig()
{
if (_cfg == null)
{
Configuration cfg = new Configuration();
cfg.Configure();
_cfg = cfg;
}
return _cfg;
}

public static void setAssembly(String value)
{
_assembly = value;
}

public static string getAssembly()
{
return _assembly;
}

public static ISessionFactory openSessionFactory()
{
if (_sf == null)
{
Configuration cfg = openConfig();

cfg.AddAssembly(_assembly);
_sf = cfg.BuildSessionFactory();
}
return _sf;
}



}

You can use singleton pattern in your helper class.

Detail about singleton pattern : http://www.dofactory.com/Patterns/PatternSingleton.aspx

It will have only one instence and global point of access to it.

Hi,
First off, are you aware of the mapping element in hibernate.cfg.xml? This element has a single attribute assembly, which tells NHibernate in which assembly to look for mappings. So you should probably exploit this feature. If you do, your code will look like this:

Hi,
I've just upgraded to nhibernate 1.2.0,
generics works nice, woo hoo!!!

But I have a problem:
if I do this:
NHibernate.ISession session = NHibernate.ISession)NHibernateHelper.NHibernateHelper.GetCurrentSession();


MyObject o = session.Load<MyObject>(PK);
///////////////////////////////////////////////////
//NHibernateUtil.Initialize(o.Name);
//NHibernateUtil.Initialize(o.IsActive);
///////////////////////////////////////////////////

session.Flush();

NHibernateHelper.NHibernateHelper.CloseSession();

return o;

I get a lazy loading error on the fields o.Name and o.IsActive!!

If I NHibernateUtil.Initialize(o.Name), I can access this field!!

It's the default behaviour???
How can I specify this lazy="false" in the mapping property??


Thanks!

"are you aware of the mapping element in hibernate.cfg.xml"

I did not know, so I went and did some research:

http://www.hibernate.org/hib_docs/nhibe ... start.html

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<!-- Add this element -->
<configSections>
<section
name="hibernate-configuration"
type="NHibernate.Cfg.ConfigurationSectionHandler, NHibernate"
/>
</configSections>

<!-- Add this element -->
<hibernate-configuration xmlns="urn:nhibernate-configuration-2.0">
<session-factory>
<property name="dialect">NHibernate.Dialect.MsSql2000Dialect</property>
<property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
<property name="connection.connection_string">Server=(local);initial catalog=quickstart;Integrated Security=SSPI</property>

<mapping assembly="QuickStart" />
</session-factory>
</hibernate-configuration>

<!-- Leave the system.web section unchanged -->
<system.web>
...
</system.web>
</configuration>

Once I setup my config as above, I was able to call the cfg.Configure()

the main key is the mapping assembly above.

Thanks for the tip to help find this and I hope if others come here they can see this as well (assuming it's correct, I am new)

Thanks!

a.gogolev,

I need a bit of assistance understanding making the session itself static like you have done:

Is it safe what you are doing above with the ISession not getting closed?

That is what I think I'm seeing?

Awesome... this just cleaned my code a bit. I was using the name-value section handler and manually adding my assembly in the initializer. I like this much more.

There's much more detailed post in the thread about 1.2.0... but the easiest way to enforce lazy behavior in your mapping is something like:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0" default-lazy="false">

or

<class name="MobysThinkTank.mobyProject.Account, mobyProject" table="Account" lazy="false">

Otherwise, you'll need to mark your properties in your class as virtual

so,

public string Name
{ get; set; }

becomes

public virtual string Name
{ get; set; }

After some further reading ( http://www.theserverside.net/tt/article ... ibernateP2 )

It would not be a good idea to use the static ISession as noted above.

From the article:

"This solution might look like it will work for Session management as well. Why not just add a static Session to the class, and create and open it just once in the static constructor? Then, all the methods could use the same Session. The answer is twofold: first, a statically shared Session might be accessed by multiple threads concurrently, which could interfere with transactional semantics. Second, a statically shared Session will spend most of its life sitting idle, and an idle Session is still holding open a physical database connection. Database connections are expensive, rare and valuable. Every data access strategy after server-side cursors has had as a goal minimizing the length of time an application holds open a connection, and NHibernate is no different. Therefore, having a static Session sitting around open and available is a poor strategy."

I think the manual has a good example of a way to design this http://www.hibernate.org/hib_docs/nhibe ... index.html as well as the article posted above.

Just thought I'd post back to answer my own question and anyone else who had the same question :)

Fwiw, I've got a session-in-view implementation from long ago that I'd be happy to share. I also have a much newer version that I'm a lot happier with but haven't really stressed yet. The new one is a modified version of the one Billy McCafferty uses in his Code Project article