Discriminator column cannot be NULL exception

[Berryl Hesh]

Hello

I am trying to map a hierarchy as table per class, and I'm getting the
following exception:

NHibernate: INSERT INTO ResourceBases DEFAULT VALUES; select
last_insert_rowid()
TestCase
'Smack.ConstructionAdmin.Tests.Data.MappingTests.ResourceMappingTests.CanSaveAndLoad_StaffMemberResource'
failed: NHibernate.Exceptions.GenericADOException : could not insert:
[Smack.ConstructionAdmin.Domain.Model.Resources.StaffMemberResource]
[SQL: INSERT INTO ResourceBases DEFAULT VALUES; select
last_insert_rowid()]
----> System.Data.SQLite.SQLiteException : Abort due to constraint
violation
ResourceBases.ResourceType may not be NULL

ResourceType is my Discriminator column as defined in the following
mapping override:

public class ResourceBaseMap : IAutoMappingOverride<ResourceBase>
{
public void Override(AutoMapping<ResourceBase> m)
{
m.IgnoreProperty(x => x.Name);
m.IgnoreProperty(x => x.BusinessId);
m.IgnoreProperty(x => x.OrganizationName);

m.DiscriminateSubClassesOnColumn("ResourceType").Length
(255);

m.HasMany(x => x.Allocations).AsSet();
}
}

public class StaffMemberResourceMap :
IAutoMappingOverride<StaffMemberResource>
{
public void Override(AutoMapping<StaffMemberResource> m)
{
m.References(x => x.StaffMember);
}
}

My understanding is that the value in the discriminator column will
default to the full class name of the subclass, but SQLite seems to
think it's getting a NULL value instead.

Can someone please enlighten me as to how I'm abusing my mapping to
get this error?

Thanks,
Berryl

[Hudson Akridge]

Would you mind doing a .ExportTo() on the config after you finish automapping? It'll help us understand what Automapper is trying to do.

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[Hudson Akridge]

And of course, posting the .hbm.xml that gets exported :)

[Berryl Hesh]

Hi Hudson - thanks for the reply.

After researching this more, I realize what I'm really trying to do
from a design perspective may have more to do with an 'optional
relationship' than relational inheritance. Ayende has a posting about
it as an NHib many-to-any mapping (http://ayende.com/Blog/archive/
2009/04/22/nhibernate-mapping-ltmany-to-anygt.aspx). There is also a
nice posting I found that approaches it as the 10% of cases where you
really do want a one-to-one relationship, and has an FNH solution
using an Alteration (http://whereslou.com/2010/01/03/extending-
nhibernate-data-with-one-to-optional-relationships). I found it as a
response to the one James Gregory wrote (http://blog.jagregory.com/
2009/01/27/i-think-you-mean-a-many-to-one-sir/) about the other 90% of
cases.

Is there an FNH officially sanctioned approach to mapping an optional
relationship fluently that you know of?

Cheers,
Berryl

On Jan 19, 5:24 am, Hudson Akridge <hudson.akri...@gmail.com> wrote:
> And of course, posting the .hbm.xml that gets exported :)
>

> On Tue, Jan 19, 2010 at 7:23 AM, Hudson Akridge <hudson.akri...@gmail.com>wrote:
>
>
>
> > Would you mind doing a .ExportTo() on the config after you finish
> > automapping? It'll help us understand what Automapper is trying to do.
>

> >> fluent-nhibern...@googlegroups.com<fluent-nhibernate%2Bunsu...@googlegroups.com>

[Berryl Hesh]

I started a different post on this here
http://groups.google.com/group/fluent-nhibernate/browse_thread/thread/7775ca4469ff3b7e?hl=en

BH