DEFINE VARIABLE cText AS CHARACTER NO-UNDO.
DEFINE VARIABLE iCount AS INTEGER NO-UNDO.
DEFINE VARIABLE iVendor AS INTEGER NO-UNDO.
DEFINE VARIABLE cDay AS CHARACTER NO-UNDO.

INPUT FROM myFileName NO-ECHO.

REPEAT:
    IMPORT UNFORMATTED cText.

    DO iCount = 1 TO NUM-ENTRIES(cText,','):
        ASSIGN iVendor = INTEGER(ENTRY(1,cText,',')) NO-ERROR.
        ASSIGN cDay = ENTRY(2,cText,',').

        /* Do more stuff as required */
    END.
END.

INPUT CLOSE.

define temp-table t-vendor
     field t-ven-num as character
     field t-day as character.

input from YourFileName no-echo.
repeat:
   create t-vendor.
   import delimiter ","
       t-vendor.t-ven-num
       t-vendor.t-day.
end.
input close.

for each t-vendor:
     /*  if your vendor.ven-num is not a character field,
         adjust as necessary */
    find vendor where vendor.ven-num = t-vendor.t-ven-num
       no-error.
    if available vendor then do:
           vendor.day = t-vendor.t-day.
    end.
    else do:
         /* this displays a message for each vendor not
            found */
         message "VENDOR NOT FOUND " t-vendor.t-ven-num
         view-as alert-box.
    end.
end.