To give access to SSRS url, instead of using the url (property or security settings), is there any option to use Queries to achieve the same thing (or) is the url way the only method?
The underlying structure of users, policies and roles is pretty complicated and everything is referenced via GUIDs. I've never really changed it by SQL and that's not supported by MS anyway. You might have some luck looking at doing it with rs.exe scripting but I've always just done it via report manager. The best way to manage it in my opinion is using AD Groups and the report manager.
If you really want to understand the underlying structure these guys did a nice 5 part blog post on it: