Pratik
I actually don't get what you are saying.
You want to have additional checks done on the data. Well, that will take additional time.
That's the very same thing that happens with any other DBMS.
Checking your data takes time.
The plus-side is: HANA will check it *once* for you. You don't have to do a thing here in your application coding and you can be sure that it will work with whatever way you use to modify the data in the table.
In short: having your cake (performance) and eat it too (check constraint) won't be happening - not even with HANA.
What you say about the stored procedure option not being viable: again I don't understand what you mean here. Of course the client would get the API . So what?
The point is that by using the API all data modification will be done the correct way.
So, no, I am not suggesting another option.
It's up to you now to be a developer and take a decision on how you want to build the system. You actually should discuss this with fellow developers, the rest of your team and the client.
- Lars