I would do it in Coda.
A ‘traditional’ application (built with a database backend and written in PHP or Delphi or C# or whatever) is really the best way to approach these things, but from what I hear in the way you ask your question, that is not going to be build by you. And you are probably not here because you can outsource a project like that.
Coda has limitations, but there will be many more updates and some will probably facilitate building better apps. I am waiting for 2 specific features that would help a lot for this type of problem:
- fine grained permissions (where some users can only see a small part of your doc)
- data protection: if it not on the screen, it shouldn’t be accessible (through browser tools, data sniffing or whatever)
But even today you can build very nice apps. You can cross doc filtered tables and update through forms. The answers to my questions in my last paragraph in my previous answer should guide you.
is the table going to be very complex, how many users, relationship to your users (are they going to try to hack your system?)
I am not sure if smartsheet can be of any help - I do know that it gets expensive when you start to have a few or more users. What I really like about Coda (among other things) is that you can have users of your app that don’t need a paid license - and that you can have as many docs as you want (at least, in my plan you can).
The one way to really find out is start building - start simple, make it work and add more features as you go. Or build something that looks like what you need and ask for some professional help here in the community - it might be worth some bucks if you can run your business better.