How to retrieve class identifier

roniburd · **Posted:** Mon May 30, 2005 2:21 pm

This one should be easy for developers of nhibernate. I'm creating a generic DAO using nhibernate and got kinda stuck in DeleteById since I have to get the class identifier.

So basically I have to do

"from " + +

Code:

sessio.Delete("from " + type.Name + where " + someWhere.GetIdentifier(type) + " = " + id.ToString()

Is there a place in nhibernate for this "someWhere.GetIdentifier(type)" ?

Thanks!

sergey · **Posted:** Mon May 30, 2005 4:45 pm

I believe you should be able to use lowercase 'id' as the property name - it's a special property that corresponds to the object's primary key.

roniburd · **Posted:** Tue May 31, 2005 10:44 am

No luck. Using underscore id in the query did not work thorwing an "Invalid column name 'id' " exception.

I'm sure there was a way to extract the identifier somehow.

roniburd · **Posted:** Mon Jun 06, 2005 2:58 pm

I finally got it right looking at the unit test (why didnt I do that first :oops: )

Anyways, if someone is reading this far is because your intrested in an answer so here goes the code on how to do a generic DeleteById

Code:

public void DeleteById(System.Type clazz, object id)
{
  try
 {
         //the next line depends on how you obtain the ISession in your app
         ISession session = NHContext.Current.NHibernateSession;

   session.Delete("from o in class " + clazz.Name + " where o.id = " +  id.ToString());
  }
  catch (Exception ex)
  {
   //log error
   throw;
  }
}

KPixel · **Posted:** Tue Jun 07, 2005 7:11 am

Or (more classic) :wink:

Code:

session.Delete( "from " + clazz.Name + " o where o.id = " + id.ToString() );