Entity collections are assumed to be based on unique rows, so you can't specify something like "allow duplicates" in the fetch. As you mapped that DB view into an entity, then you should:
- specify the distinct at the DB view level
- specify the PK for that entity in "identifying fields" of the entity.
- you also could filter out duplicates "after" the collection if fetched using in-memory tactics, but I guess that is not what you are looking for.
If this doesn't fit to you, then maybe you shouldn't map that view into an entity. You should map it into a TypedView instead, so you can specify the "allow duplicates" parameter in the typed view fetch.
The "duplicate" concept is narrow in a DB view. What is duplicate? The full data row? Some PK? some subset of columns?
