Hi Nehal, I'm not totally sure what you mean by that, so excuse me if my answer is a little bit off!
First of all, you can set any external symbol ({1}, {2}, {3}, ..) like this: (set '{2} 123)
However, this is more suitable for debugging mode because except than debugging, you do not know the external symboll for each data has.
And note that {1} has a little bit special role because it is the root of the database, this is why you can set the value via the *DB global variable.
Let me know if you have more questions, this topic is really a little bit hard to explain&understand in the beginning.