Firstly, thank you.
Yes, I have the SQL trace activated on my server and I can see SQL statements are traced when I executing scripts using HANA Studio SQL console, but not my XS app.
Anwser your 2nd question: I want to trace every possible SQL statements, like HANA Studio's SQL Console. Actually, my team and I are developing a web based HANA SQL Console, which is a part of HANA Web IDE.
In HANA Web IDE, there is as well a component named Trace, which allows user to view HANA trace files content, including SQL trace.
Because the application is XS application, I don't know whether there is any limitation.