Security in PC-Client/UNIX Server environment

In our line of work, it is critical that we know WHO did WHAT to the DATABASE when. Well, using the dumb terminal approach of UNIX, we have that. But, I admit to being completely confused about the front-end on a PC thing. If we use our PC app to determine who you are, can someone not simply hack something onto a PC, and call themselves that? If we have to determine who the user is at every update, then (it would appear) that we will have to do that within the engine...no? Can anyone enlighten us on this one? B. ------------------------------------------------------------------------ |Brian P. Hampson Internet: brian@asl-labs.bc.ca | |System Administrator, | |Analytical Service Labs Fidonet : Brian Hampson 1:153/733 | |Vancouver, BC | |+604-253-4188 | | Specialists in Environmental Chemistry | | | ------------------------------------------------------------------------