I have a main table with ProjectID and Name. ProjectID is the foreign key in 2 (or more) 'geometry' tables as a Project can have points AND lines associated with it. The screenshot is from ArcPro. The tables are shown in the screenshot as well.
What I'd like is to have these show up as a unified dataset (from user's perspective) in ArcGIS Online webmaps (could be done through a temporary join?). When a feature (point or line) is clicked, it brings up Project Name, and a user can edit Name (in the Projects table) corresponding with the selected feature. I'm not familiar with how to do this in ArcPro/ArcGIS Online.
I'd rather not replicate Name across all related tables as that leads to data integrity issues, and changes in one layer (point) won't reflect in the others (line). In an SQL database (which I'm familiar with), it'd be something like
Update Projects set Name = 'NewProjectName' where ProjectID = [ProjectID of clicked/selected point or line]
Any documentation on how to do something like that in ArcPro/ArcGIS Online webmaps/webapps? TIA!
I don't know how or even if it can be translated to an ArcGIS Online webmap but you can set up relationships in ArcPro. Your idea of creating temporary joins is attractive but would fail because the joining table (your project names) would be read only this is discussed in the help here.
You are left with relationship classes. Here is an example of setting up a relationship, f1 would be for example your point layer and t1 is your projects names table
Repeat for your polyline layer.
Then when you select a point and you are on the Edit tab and have opened the attributes panel then by expanding out your selected feature you see your related table and editing the name there means if you select a polyline you will see your updated project name.