CAF CORE COLLECTION_ASPECT_KEY error

Question

I have a simple entity "Approver" with attribute functions (string) and contacts (String), cardinality 0:n for both.
I build UI object based on Object Editor pattern for this Approver Entity service. Also build the UI object based on Relationship Tab patteren for the Approver Functions and Contacts (attributes).
When I test the UI (Object editor pattern based) for entity service. It let me add the record to functions and contacts tab, but when clicked on save returns following error.
Key (or KeyList) [localKey@11e75a9]  is no Key (KeyList) of type COLLECTION_ASPECT_KEY_Approver
At one point this was working fine. I tried to recreate the Entity Service, UI pattern objects and now both the functions and contact tabs not working. Can not save the records added in those tabs.
Do I need to do any coding in Entity Service? Is there a documentation that I refer to resolve this error?
SAP has developed CAF-CORE technology, I guess it will be nice if they can really put out good documentation and tutorials with complex examples.
Thanks

Answer 1

Hi ANdre,
I have one entity "Approver"
with following attributes
Attribute Name            Type      Cardinality
id                     String      0..1
name                   String      0..1
functions              String      1..n
hrContacts             String      1..n
I would have idealy like to have recusrive relationship, because User or employee plays different roles, like, assistant, hrContact, approver, supervisor. Employee could be associated with multiple functions. To keep the things simple I am having the functions and hrContacts as field on the entity, idealy would have like to have, reference to another entity.
I guess the problem is with automatic code generated for Entity service and UI patteren. It is expecting something at some place and that's not well documented.
I have another Entity service with similar structure for Vendor entity and all the UI pattern work fine, that including Object Editor and Relationship tab.
Thanks