DeDuplicating Call Log Records

Hi,

I would like to understand how to deduplicate the call log data I have received via the api. Initially I believed the id field to be unique primary key, however I can see that there multiple instances of the id key duplicating, which I imagine being related to the various legs involved in some of the calls. I would appreciate it if anyone could provide me with the fields they have used to generate a true unique primary key.

Regards