Identity Generator for id in child table.

Hi again,

I hope you can help me with a problem with saving test code_

ISession session = null;
Attribute attr = null;
AttributeValue attrValue = null;
try {
session = NHibernateHelper.OpenSession();

attr = new Attribute();
attr.Label = "Name";
attr.MetaId = 71;
attrValue = new AttributeValue();
attrValue.Attribute = attr;
attrValue.Value = "Daniel";
attr.AttributeValues.Add(attrValue);

using(var tx = session.BeginTransaction())
{
    session.Save(attr);
    tx.Commit();
}
session.Close();
} catch(Exception ex)
{
MessageBox.Show(ex.ToString(), "Exception");
}

I have a parent table Attribute with a primary key AttributeId using a sequence as the identity generator, and a child table AttributeValue with a primary key AttributeId that is a foreign key mapping to Attribute.

The problem is that i don't now how to set the identity generator on the AttributeId column for table AttributeValue. It needs to get its value from the Attribute table.

I have tried to use an Interceptor to set AttributeId to the value from Attribute.AttributeId but that only generates this exception on the commit: "identifier of an instance of TestModel.AttributeValue was altered from 0 to 264059"

I have attached an image of the model and the SQL code to create the tables.

Is there a way to get the child table to get the id from the parent table ?

Thanks, Daniel

The programs and versions i have:

NHibernate Designer Version: 2.0.255.19857 Visual Studio 2010 with SP1 Database: PostgreSQL 9.1 Windows 7 Enterprise 64-bit

Update:

Hi,

I have found a example of my problem being fixed by using generator class='foreign'. Se here: http://stackoverflow.com/questions/2799044/nhibernate-one-to-one-mapping-issue-with-child-object-insert-error And by changing the generated mapping for the id in my AttrbuteValue class to:

<id name='AttributeId'
    column='`AttributeId`'
    >
  <generator class='foreign'>
         <param name='property'>Attribute</param>
  </generator>
</id>

It works but if i rebuild the change is lost, is there a way to set this in NHibernate Designer ?

Thanks!

We don't currently support generator class='foreign', but I'll see if we can get it added for you.

As an interim workaround, you can modify the generated mapping by implementing the CustomizeMappingDocument partial method. This allows you to post-process the XML at runtime, before the configuration system reads it. See http://www.mindscapehq.com/help/nhdesigner/Help%20Topics/CustomisingGeneration.html for info about how to do this. But hopefully we'll be able to get you an update shortly so this won't be necessary!

Hi Daniel,

The next nightly build (available from about 1200 GMT) will include a Foreign option for Identity Generator. Let us know if you run into any problems with it!