Java applets access to internal DBs

[jsong @ amer . net (Jenjen Song)]

Can anyone help me with the following questions:

By using Java applets, can a database query be handled on a client machine
directly with a database, i.e., without passing through the Web server? 
if YES, then can Java applets replace the function of CGI?
what kind of security should use for the database access to authenticate
which Java applet can go in and which should not?

Thanx in advance.