Validating input parameters using exception handlers

Question

Hi
I have a procedure which works in a similar way to the following:
PROCEDURE main (p_date_from times.id%TYPE)
l_time_from varchar2(40);
BEGIN
l_time_from:=p_date_from
IF l_time_from IS NULL THEN
    l_time_from:='23:59';
ELSIF NOT regexp_replace(l_time_from,'.[0-9]{2}:.[0-9]{2}') THEN
    RAISE invalid_time
END IF;
EXCEPTIONS
  WHEN invalid_time THEN
    dbms_output.put_line('Not a valid time');
END main;I want to validate p_time_from parameter so that it only accepts the following format 'NN:NN' i.e. '22:31'. I've thought that using a regular expression would work within an IF statement, however as you can see my syntax is poorly constructed at best and doesn't actually work. Is there a better way of doing this??
Many thanks
Edited by: tri_harder on Dec 4, 2008 11:50 AM

Answer 1

Hi,
A better solution...
CREATE OR REPLACE PROCEDURE proc_main(p_date_from IN times.id%TYPE,
                                      p_code      OUT NUMBER,
                                      p_message   OUT VARCHAR2) IS
    v_date_from times.id%TYPE := '23:59';
    v_date      DATE;
    invalid_minute EXCEPTION;
    PRAGMA EXCEPTION_INIT(invalid_minute, -1851);
    invalid_hour EXCEPTION;
    PRAGMA EXCEPTION_INIT(invalid_hour, -1850);
    invalid_format EXCEPTION;
    PRAGMA EXCEPTION_INIT(invalid_format, -1858);
BEGIN
    -- Initialization
    p_code    := 0;
    p_message := 'Succesful';
    IF p_date_from IS NOT NULL THEN
        v_date_from := p_date_from;
    END IF;
    -- This raises exception
    v_date := TO_DATE(v_date_from, 'HH24:MI');
EXCEPTION
    WHEN invalid_minute
         OR invalid_hour
         OR invalid_format THEN
        -- You must handle the exception
        p_code    := SQLCODE;
        p_message := SQLERRM;
END proc_main;Regards,