Storing parameters in asterisk db

I want to let my subscribers set redirecting numbers for forwarding in the internal database under their endpoint name in the format (endpoint name/parameter name). For example, to set unconditional forwarding, one would enter 21phone number#. With what function can I identify the current endpoint name? I cannot understand. I want to use the Set(DB({ENDPOINT}/CFU_NUM)={number}) dialplan command/

I have only found I can use caller ID.

You would need to use callerid, or some other mechanism. It really depends on what channel driver is in use.

Thank you, I have done this with caller ID.