CODEWITHSUNDEEP
nhibernatefluent-nhibernate
misnomer
misnomer

Reputation: 2594

Mapping the reverse of a ReferencesAny?

I have two entity classes (with a common interface, for easy automapping), where one has a generic reference to the other:

public interface IModelClass
{
  Guid Id { get; set; }
}

class Order : IModelClass
{
  public virtual Guid Id { get; set; }
  public virtual ISet<Attachment> Attachments { get; set; }
}

class Attachment : IModelClass
{
  public virtual Guid Id { get; set; }
  public virtual IModelClass AttachedTo { get; set; }
}

I can define the generic reference with ReferencesAny:

mapping.ReferencesAny(x => x.AttachedTo)
       .EntityTypeColumn("entity_type")
       .EntityIdentifierColumn("entity_id")
       .IdentityType<Guid>()
       .MetaType<string>()
       .AddMetaValue<Order>("ORDER")
       .Cascade.None();

And this works fine, as long as I only work with attachments directly and don't try to do things from the Order side. What I want though, is to map the reverse of the relationship - i.e. what would normally be handled by:

mapping.HasMany(x => x.Attachments)

so that I can, say, add attachments to the Order's collection and get them persisted without having to manually go through and set up/save each of the attachments (and I'd have to start passing the session around to get the attachments committed in the same transaction). This doesn't work - it just works normally and creates an order_id column on the attachment table.

Is there some way to set up this mapping so that it 'works'?

Upvotes: 0

Views: 233

Answers (1)

Firo
Firo

Reputation: 30813

mapping.HasMany(x => x.Attachments)
    .KeyColumn("entity_id")   // to give it the right column to use
    .Where("entity_type = 'ORDER'")  // makes sure that only attachments for the order are loaded
    .Inverse()
    .Cascade.AllDeleteOrphan(); // or .Cascade.All(); if Attachments should stay without

Upvotes: 2

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