Drop-down filtering of object type metadata

Question

Hi community, 
 I am trying to find the best way how to make filter object types drop-downs. In our case, we have an object type representing Countries. We use Country metadata in different document types and we need to apply different filtering in different cases. My approach originally was to use automatic and effective permissions on object types and to apply permissions based certain filters we are getting from our database. So drop-downs of countries were filtered always according to those effective/automatic permissions. This was fine until we get requirement to open countries drop-down for specific document types. 
 The trouble is if I remove effective permissions on object type I will satisfy certain document types where I need to provide all countries. Unfortunately other document types where I need to apply our country-level permissions (for certain document types, people should only see subset of countries in document types). I would need somehow to filter countries in other document types based on specific filter. I am wondering how to do this. 
 Does someone have some ideas about this one? 
 Thanks. 
 Dejan

Tom Humm · Answer

This sounds like a many to many parent/child relationship, it can be achieved but requires leveraging Object Types rather than Value lists. Properties specifying the relationships of each country, doc type/class and specific metadata on the Doc-Type objects specifying what countries are allowed. I would anticipate needing some hidden properties to help drive the filtering. Generally when this has come up in the past, alternative approaches have been taken since these complex configurations can prove to be difficult to maintain in larger/high object count deployments. It can also lead to user confusion as the required infrastructure to support this type filtering necessitates additional fields that can impact views and advanced search configuration requirements. 
 An alternate approach you might consider would be providing the list of acceptable countries for each doc type as default values through a metadata card configurations. Users would be provided the list and could then remove the countries not pertinent to the specific document they are creating, the quantity of countries for each doc type would need to be considered though since going through a very long list would be frustrating and likely not make sense.