For those who wish to maintain object graphs or to persist api domain objects authoritative documentation of the field(s) that define a unique key for the object would be of value.
Some are obvious and some not so obvious and this post should serve as a discussion leading to a definition, as can be arrived at.
Please contribute your observations and if you are one of the few with definitive knowledge, your input is expressly solicited.
Seems Obvious
answers-answer_idbadges-badge_idcomments-comment_idquestions-question_idusers-user_idrevisions-revision_guid(withrevision_numberas a sort field?)tags-name(+user_idwhen appropriate)
Not So Obvious
It seems the best we can do here is a 'soft' key dependent on the very slim chance of a collision on the date field.
user_timelines- ??post_id+user_id+timeline_type+creation_datepost_timelines- ??post_id+user_id+timeline_type+creation_daterep_changes- ??user_id+post_id+on_date
user_idfield as part of a composite key. clear? – Sky Sanders Aug 8 '10 at 1:04/users/{id}/tagsaccepts multiple keys so the tags response will contain tags from multiple users, theuser_idfield is necessary for segregation. – Sky Sanders Aug 8 '10 at 4:24