I'm getting some odd results from my FieldMappings and am wondering if it can be explained.
Using Append, I'm combining five FCs into one existing FC using Delete Feature and Append. All FCs are in a different geographic area so there are no features overlapping.
The Target FC contains a field Asset_ID. All five sources also have Asset_ID, but I don't want to use one of them, instead I'm trying to map to eg. SomeOtherID for one of the sources The Append still seems to be trying to use the Asset_ID field for all sources.
I've noticed that if a Asset_ID value is NULL, it then reverts to the SomeOtherID. That made me think about the Merge rule, so I switched to Last, and it worked fine. so.... is the merge rule referring to the order of fields in my source tables?.. This is not what I thought the rule was for, why would it even still consider the Asset_ID when I've told it to go to another field?
It feels like it takes either the target field and looks for it in all the sources by default, or maybe it takes each of the mappings and tries to look for them in all the sources?....
if anyone has some time to test a scenario like this it would be greatly appreciated.
10.2 and 10.4