I don't think you would want to force a user to make any particular entries
when entering a date. Set the field to a date field and let Access do all
the work. Regardless of how the user ENTERS the date, Access stores it as a
number that represents the date. You can determine how to display the
figure on forms, reports, and queries using the format property (or a format
function).
Access will correctly interpret a wide variety of date formats,
including this one. You don't need to set any input mask at all; if
you set the Format property of the textbox to
dd-mmm-yy
the textbox will show 06-Jan-05 (whether the user enters it that way
or types "1/6" or "1/6/2005" or "Jan 6" or any other interpretable
date). Note that the date is stored internally as a number, not in
*any* specific format.