Hi there,

I have generated classes A and B where B inherits from A.

I've noticed that B's relations are inherited from A. So if I have a third table C which is related to A and I want to join C to B then how do I do this? I can join C to A but what if I only want it to join when an A is also a B?

If the inheirtance relationship between A and B wasn't established then I could just do C joins to A and then join A to B but LLBLGen doesn't automatically create a relation between A and B.

Hope that makes sense!

Cheers, Ian.

I can join C to A but what if I only want it to join when an A is also a B?

You could: 1. Hide the _A.SomeCId -C.SomeCId _relation (both sides). 2. Create a relation between B.SomeCId - C.SomeCId. Note that B.SomeCId is an inherited field from A.

OK! Why doesn't LLBLGen automatically generate this relation which would have been there had it not been for the inheritance between the entities?

LLBLGen automatically generates the relations based on your DB schema metadata. The normal usage for relations in a hierarchy is that the subtypes inherit the supertype relations. But you want to add the relation only to subtype. That must be done manually.

Hi David,

I'm in this same situation.

I want to be able to go from C -> A (BaseType) and from C -> B (SubType)

To go from C -> B, I would need to hide the relation from C -> A? Can I only have one or the other?

Please confirm the best way to access both related entities & their subtypes. Thank you very much!

Ryan

When you need to go from C -> B (SubType), you may use the relation from C -> A and use a Type Filter for B.

Hi Walaa -

If I do that, won't I suffer these very ugly side effects?

1.) I will have to manually build all the SubType prefetch paths 2.) What's worse - I won't be able to get a strongly typed collection, correct? So the Filter approach won't let me do:

• BaseTypeCollection > SubTypeCollection
• EntityView(of BaseType) > EntityView(of SubType)
• EntityCollectionBase(Of BaseType) > EntityCollectionBase(Of SubType) I need strongly-typed collections... We're using generics extensively for Entities & EntityCollections. We have several layers of inheritance. I don't want to be stuck passing the SuperBaseTypeCollection around to all my higher-level functions.

What's the best approach here for C -> A & C -> B? Couldn't we simply create both in the designer? I've tried, and I get compile errors.

Please tell me these 2 relations aren't mutually exclusive. Many thanks!

Ryan

I don't think any of these are applicable if you used a collection of the SubType.

e.g. Say you want to fetch Bs(sub) filtered by some field on C using the relation from C to A(super). The following code should do the job.

var bucket = new RelationPredicateBucket(C_Fields.SomeField == xyz);
bucket.Relations.Add(SuperEntity.Relations.C_Entity...)

var subs = new EntityCollection<SubEntity>();
adapter.FetchEntityCollection(subs, bucket);

Hi Walaa -

Yes, but then my EntityGraph will be disconnected. Merging / Diffing the EntityGraph won't work. EntityGraph listening for deletes will not detect B's deletes. Recursive Saves of C will not work. Because C (my Root Entity) has no clue B even exists.

The goal is to walk the relations in the Graph. I need actual relations from C -> A and C -> B.

I have no problem manually creating these relations in the designer. But it's not working for me.

This seems simple. Shouldn't this be possible?

Ryan

I have no problem manually creating these relations in the designer. But it's not working for me.

Would you please explain in more details the "it's not working for me" part. Thanks.