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.
revision_numberas a sort field?)
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.