Opinions Welcom on One Security Problem

Hello All! I bring my apologies in advance since this problem is somewhat common, but, IMHO, it's significant for the developer working with any particular DBMS server. Some of the database applications get designed to work in Intranets of mixed nature, where conventional front-ends, Java standalone and applets, and active Web pages coexist. Surely, such systems are very likely to comprise various types of client machines. Some folks insist on implementing the 'enter name/password once' technique in such systems. Surely, there are serious difficulties, and some designers avoid them by emulation of trusted connections in different manners. I have my own opinion of such systems, but, it's only my humble opinion. So, I'll be very grateful for some ideas/opinions on the following problems: 1) Can systems based on emulation of trusted connections in a very heterogeneous environment be considered reasonably secure for corporate use? 2) Is it safe to create a special hidden login for the Web server, allowing it access server user passwords stored in non-encrypted form, en claire? 3) Are trusted connections safe enough on the machines where macro language supporting programs, mailing software and Internet browsers are widely used? 4) Is it safe to use Web components implementing the trusted connections, both native and emulated? All the hints, answers, opinions and discussion will be greatly appreciated, and, IMHO, will help to reduce the amount of bad software. TIA FWIW Regards Igor I. Lisyansky