What is the difference between the "WebId" and "Id" that are returned with pretty much everything in PI Web API? Is one more unique than the other?
The webid that is returned in PI Web API is a combination the path of the attribute and the id of that attribute. So, the WebID is slightly more unique as it is possible, but highly uniquely, that two AF Servers each create an attribute with the same ID.
There is extra information bundled in a WebID as there could be many AF servers and many AF databases registered to the same PI Web API service and having that extra information allows the service to more easily pick out where a particula attribute lives.
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