Automating field population in Word Document

Hello,

I would like to populate some of the many fields in a Word Document from a
database based on the value entered in one field in the Document after the
user tabs out of this one field.

I could do this using a macro and then hide that using a password. I was
wondering if Office 2003 provides a simpler way to do this through Smart
Document technology. Essentially I would like to hide my database connection
in a compiled dll and not have to worry about protecting the macro using
passwords.

Would appreciate any thoughts regarding this or pointers to papers/online
examples.

TIA,
Sanjay.