What is the difference between _id and thread_id?

Question

I find there are two fields _id and thread_id in SMS database, What is the difference between _id and thread_id ? If I want to delete a sms by ID, which field should I use? _id or thread_id ? Thanks!

Answer 1

the _id is the primary autoincrement key for the sms ContentProvider, the thread_id is the id of a particular conversation