...in a many-to-one or many-to-many relationship, using the ArcMap editing tools and a relationship class?
It seems that if you want to relate many tabular records to one spatial feature you can use the attribute editing dialog and selection sets to perform this task in a single action, but if you want to relate a single (or many) tabular record to a many spatial features (in a related feature class) then you cannot do it without processing each spatial record one at a time.
This is problem if I want to relate say, 100 road segments, to a single row (or many rows) in a related table. I will have to expand the tree of selected road segment records (in the attribute editing dialog), right-click on each of the relationship class in the expanded tree and select the "Add Selection" menu item. I want to be able to relate all of the selected road segments in a single action.
I realize that if the relationship is many-to-one I could simply populate the foreign key identifier from the record in the related table to the 100 road segments using the field calculator, but there is no simple way of doing this if the relationship is a many-to-many relationship.