Anyone have an idea on how i can create a column check constraint on a char(15) column that only allows the digits 0-9 and the characters A-F?

In fox pro I did this...

FOR i=1 TO LEN(ALLT(THISFORM.txtnic.VALUE))
   IF !INLIST(SUBSTR(ALLT(THISFORM.txtnic.VALUE),i,1), '1','2','3','4','5','6','7','8','9','0','A','B','C','D','E','F')
      warningmessage=warningmessage+CHR(13)+'Invalid NIC address. (Non hex digit)'+' "'+SUBSTR(ALLT(THISFORM.txtnic.VALUE),i,1)+'"'
       THISFORM.txtnic.SETFOCUS
       oktosave=.F.
   ENDIF
ENDFOR

but im not sure if you can loop through each character. Any help is appreciated.

Eric Stephani