Consistency GUIDs are a detection strategy that allows an
application to detect partial updates. A consistency GUID (Globally
Unique IDentifier) is applied to each object in a related set. In
implementation, a source application generates a new GUID and
applies it to each object it updates in the set of related objects.
It then applies the new GUID to the rest of the objects in the set,
and finishes by applying the new GUID to the "master" object.
Typically, the "master" object will be a container that is the
parent of the other objects in the set.
Some important considerations:
Consistency GUIDs combined with object counts or checksums are
more effective than consistency GUIDs alone, because the
application reading the objects may not know how many objects with
the GUID should be present.
Applications must generate their own GUIDs (a Microsoft® Win32®
API, UuidCreate, provides this function), and not use the
system-generated GUIDs found in an object's objectGUID
attribute. This is because a consistency GUID needs to change each
time the set of objects is updated. Object identity GUIDs found in
objectGUID never change after the object has been
created.
Consistency GUIDs assume that no object is shared among sets,
so each set can have a unique consistency GUID.