How to determine which row in contacts database has been updated
<p>I am writing a backup application and need to know which records in the contacts database have been updated, so that I can backup only those records. I have looked at the documentation and it seems that there is a "DIRTY" constant field in ContactsContract.RawContacts class, which is supposed to be set to "1", for the rows that are  updated. But it is not clear to me as to when will this field get cleared to "0". Can someone provide me example code on how to use this? Can this field be used to determine if a contact has been added or updated?
If this is not the correct way to achieve what I am trying to do can anyone suggest me another way. I am also aware that I can use the RegisterContentObserver() call to identify whenever there is a change in the Contacts database but this will require my application to be running always in the background, which is way too expensive and I do not want to do that.
If there is anyway to extract the timestamp when the various contacts have been added or updated that would be perfect too, but I cannot find how to do that.
Any help is very much appreciated.</p>
