I have a Collector app for gather asset data points. I'm working on setting up a domain field for over 10000 different room features across nearly 100 sites. I want the user to be able to associate the asset point in Collector with the room that it's closest to. I've converted the rooms for all sites table to a domain, with the unique space ID as the code, and the room name or number as the description. I have another field where the user chooses the site. In the rooms dropdown, I want the user to only be able to choose the rooms associated with the particular site they are visiting.
This would be a one to many relationship. For example: Site A has 20 rooms. When Site A is chosen in the Site dropdown in Collector, I only want the user to be able to choose from one of those 20 rooms, not see 10000+ in the Room dropdown. Is this even possible with Contingent Values? So far in design view, it looks like it's all one to one relationships, like I would have to create a contingent value for every single room.
For the question about whether this is possible using Contingent Values, yes, it seems like it would be. If we look at Work with contingent values—Geodatabases | Documentation and follow the example through the part showing how it would be set up:
It definitely looks like you could set it up for site A room 1, site A, room 2, etc. etc.
For 10,000 rooms! You might want to explore the required schema in Import Contingent Values—Data Management toolbox | Documentation , set everything up in Excel, create a csv and import the values.
But before you go through all of that, if the goal is to use this in Collector, this has been asked before: https://community.esri.com/thread/235234-contingent-values-in-collector-for-arcgis and as far as I can tell, Contingent Values functionality isn't yet supported outside of ArcGIS Pro. It might be worth getting a more official answer from somebody in the Collector for ArcGIS space though.