I am trying to populate one attribute field (Main) based on a spatial relationship in a file geodatabase. I have mains and laterals. Our mains have a field called "Main_ID". I want to populate our lateral attribute field "Main" based on the main that the lateral touches. Seems like a pretty simple problem. I've tried the spatial relator, but that actually adds the geometry (essentially doubling the number of laterals). I don't want to write out or replace any geometry, just populate that one attribute field.
Any suggestions?