Check out rick's suggestion, it's better than mine.
currentuser() will only work if security is set up otherwise currentuser
will always be admin.
If you set up security, each user will have their own userid. That can be
determined by the currentuser() function. Save that data to a field in your
table. When you run a query use as a parameter the field in your table must
equal the currentuser(). Use a form to access the data, and don't give
access to the original table. A user with admin permissions can change a
userid for a user that quits to a user that is still ther if necessary, that
can be done in a query also.