NHibernate - not-null property reference a null or

问题:

I'm getting this exception (Full exception at the bottom):

NHibernate.PropertyValueException was unhandled by user code
 Message="not-null property references a null or transient
valueClearwave.Models.Encounters.Insurance.Patient"
 Source="NHibernate"
 EntityName="Clearwave.Models.Encounters.Insurance"
 PropertyName="Patient"

I've done a lot of Googling and it seems the most common cause for that error is when an association is bi-directional but only one half has been set. As in: Insurance.Patient = Patient is called but Patient.Insurances.Add(Insurance) is not. I do, in fact, have a scenario like that but I've checked the object just before calling Save with it and both Insurance.Patient and Patient.Insurances[0] are the right objects.

The other possibility that this exception seems to reference is a transient value. In my case every object is transient so I'm suspecting the root of my problem is here. However, everything needs to be transient right now because nothing has been saved yet. I would expect NHibernate to persist things rather than complain that they are not persisted.

Here are some snippets from my mappings (fluent):

       public PatientMap()
       {
           WithTable("tPatient");

           Id(x => x.Id, "uid_Patient").GeneratedBy.GuidComb
().Access.AsReadOnlyPropertyThroughCamelCaseField();

           HasMany(x => x.Insurances).WithKeyColumn("uid_Patient")
               .Cascade.All()
               .Inverse();

          ...
       }

      public InsuranceMap()
       {
           WithTable("tPatientInsuranceInfo");

           Id(x => x.Id,
"uid_PatientInsuranceInfo").GeneratedBy.GuidComb
().Access.AsReadOnlyPropertyThroughCamelCaseField();

           References(x => x.Patient, "uid_Patient").Not.Nullable
().Cascade.All();

           ...
        }

So, what could be the issue?

---

NHibernate.PropertyValueException was unhandled by user code
 Message="not-null property references a null or transient
valueClearwave.Models.Encounters.Insurance.Patient"
 Source="NHibernate"
 EntityName="Clearwave.Models.Encounters.Insurance"
 PropertyName="Patient"
 StackTrace:
      at NHibernate.Engine.Nullability.CheckNullability(Object[]
values, IEntityPersister persister, Boolean isUpdate)
      at
NHibernate.Event.Default.AbstractSaveEventListener.PerformSaveOrReplicate
(Object entity, EntityKey key, IEntityPersister persister, Boolean
useIdentityColumn, Object anything, IEventSource source, Boolean
requiresImmediateIdAccess)
      at
NHibernate.Event.Default.AbstractSaveEventListener.PerformSave(Object
entity, Object id, IEntityPersister persister, Boolean
useIdentityColumn, Object anything, IEventSource source, Boolean
requiresImmediateIdAccess)
      at
NHibernate.Event.Default.AbstractSaveEventListener.SaveWithGeneratedId
(Object entity, String entityName, Object anything, IEventSource
source, Boolean requiresImmediateIdAccess)
      at
NHibernate.Event.Default.DefaultMergeEventListener.EntityIsTransient
(MergeEvent event, IDictionary copyCache)
      at NHibernate.Event.Default.DefaultMergeEventListener.OnMerge
(MergeEvent event, IDictionary copyCache)
      at NHibernate.Impl.SessionImpl.FireSaveOrUpdateCopy(IDictionary
copiedAlready, MergeEvent event)
      at NHibernate.Impl.SessionImpl.SaveOrUpdateCopy(String
entityName, Object obj, IDictionary copiedAlready)
      at
NHibernate.Engine.CascadingAction.SaveUpdateCopyCascadingAction.Cascade
(IEventSource session, Object child, String entityName, Object
anything, Boolean isCascadeDeleteEnabled)
      at NHibernate.Engine.Cascade.CascadeToOne(Object child, IType
type, CascadeStyle style, Object anything, Boolean
isCascadeDeleteEnabled)
      at NHibernate.Engine.Cascade.CascadeAssociation(Object child,
IType type, CascadeStyle style, Object anything, Boolean
isCascadeDeleteEnabled)
      at NHibernate.Engine.Cascade.CascadeProperty(Object child,
IType type, CascadeStyle style, Object anything, Boolean
isCascadeDeleteEnabled)
      at NHibernate.Engine.Cascade.CascadeOn(IEntityPersister
persister, Object parent, Object anything)
      at
NHibernate.Event.Default.AbstractSaveEventListener.CascadeBeforeSave
(IEventSource source, IEntityPersister persister, Object entity,
Object anything)
      at
NHibernate.Event.Default.DefaultMergeEventListener.EntityIsTransient
(MergeEvent event, IDictionary copyCache)
      at NHibernate.Event.Default.DefaultMergeEventListener.OnMerge
(MergeEvent event, IDictionary copyCache)
      at NHibernate.Impl.SessionImpl.FireSaveOrUpdateCopy(IDictionary
copiedAlready, MergeEvent event)
      at NHibernate.Impl.SessionImpl.SaveOrUpdateCopy(String
entityName, Object obj, IDictionary copiedAlready)
      at
NHibernate.Engine.CascadingAction.SaveUpdateCopyCascadingAction.Cascade
(IEventSource session, Object child, String entityName, Object
anything, Boolean isCascadeDeleteEnabled)
      at NHibernate.Engine.Cascade.CascadeToOne(Object child, IType
type, CascadeStyle style, Object anything, Boolean
isCascadeDeleteEnabled)
      at NHibernate.Engine.Cascade.CascadeAssociation(Object child,
IType type, CascadeStyle style, Object anything, Boolean
isCascadeDeleteEnabled)
      at NHibernate.Engine.Cascade.CascadeProperty(Object child,
IType type, CascadeStyle style, Object anything, Boolean
isCascadeDeleteEnabled)
      at NHibernate.Engine.Cascade.CascadeOn(IEntityPersister
persister, Object parent, Object anything)
      at
NHibernate.Event.Default.AbstractSaveEventListener.CascadeBeforeSave
(IEventSource source, IEntityPersister persister, Object entity,
Object anything)
      at
NHibernate.Event.Default.DefaultMergeEventListener.EntityIsTransient
(MergeEvent event, IDictionary copyCache)
      at NHibernate.Event.Default.DefaultMergeEventListener.OnMerge
(MergeEvent event, IDictionary copyCache)
      at NHibernate.Event.Default.DefaultMergeEventListener.OnMerge
(MergeEvent event)
      at NHibernate.Impl.SessionImpl.FireSaveOrUpdateCopy(MergeEvent
event)
      at NHibernate.Impl.SessionImpl.SaveOrUpdateCopy(Object obj)
      at Clearwave.Models.Data.Util.RepositoryBase`2.Save(EntityType&
entity) in C:\Projects\ClearWave\Src\Common\Domain Models
\Clearwave.Models.Data-NHibernate\Util\RepositoryBase.cs:line 25
      at IntegrationWebServices.FromMirth.SubmitMessage(Message
theMessage, Guid providerOrganizationId)
      at SyncInvokeSubmitMessage(Object , Object[] , Object[] )
      at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke
(Object instance, Object[] inputs, Object[]& outputs)
      at
System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin
(MessageRpc& rpc)
 InnerException:

回答1:

Another possibility is that you're saving an entire object graph, and that graph is circular, and items cannot be null. You could be giving NHibernate no legal order in which to do the inserts. (It should produce a better error message, but it produces this one).

Without seeing the rest of the source, it's hard to be of more help. Try removing entities from the mappings (and not saving them) until you can figure out what is causing the problem.

回答2:

not sure if it helps but this did it for me.

<many-to-one name="Company" column="CompanyId" cascade="all" not-null="true"/>

cascade="all" was what I missed out before

回答3:

I've had this problem recently and it has to do with the way NHibernate bi-directional relationships are persisted. You have the mapping correct and therefore NHibernate will perform the Patient insert no problem. Then NHibernate needs to take the key from Patients and cascade that into Insurances. Since the Patient does not yet exist, the keys do not exist and it cannot perform the second insert. The key is to set the relationship via code prior to persistence, something like this:

patient = new Patient();
patient.Insurances.Add( new Insurance{ Patient = patient } );
repository.Save( patient);

Now it was foreign to me that you have to set the Patient property on the collection item, but if you ignore persistence all together you will be setting this in code independent of your persistence strategy.

回答4:

This worked for me. The important things here are that we have References with Cascade.All() and we don't have Inverse() on HasMany

public PatientMap()
{
    HasMany(x => x.Insurances)
        .WithKeyColumn("uid_Patient")
        .Cascade.All();

    ...
}

public InsuranceMap()
{
    References(x => x.Patient, "uid_Patient")
        .Not.Nullable()
        .Cascade.All();

    ...
}

回答5:

It looks like the exception originates at line 25 of your RepositoryBase.cs file, presumably when a Save() is called on one of your transient objects. Which one is being saved?

Also, and it might be unrelated since I'm unfamiliar with the Fluent syntax, should the child object (the insurance in this case) have .Cascade.All on it? In standard XML schema syntax, only the parent mapping has cascade="all" on the collection of child objects.