question about largeValueMapSQL sample

[claudiobosticco]

While still learning the great features of sqldatasources, I was interested In the largeValueMapSQL sample.
I just noticed that the itemNames in the list while filtering and editing are duplicated.
I'm wondering if it's intended behaviour or not (bug or other).
If yes, does it mean that the only right approach to display distinct items (and ordered - the only feasible option for a select with many items) in the picklists is to specify an optionDataSource?

[Isomorphic]

It's a data problem, someone has saved multiple items with different primary keys but the same itemName. So those are distinct items as far as the system is concerned (and they should be).