local function inside PL/SQL script - sql

Question

I'm trying to execute this code in Oracle 10 SQL Developer:
FUNCTION is_valid_date (p_val in VARCHAR2, p_format IN VARCHAR2 )
RETURN numeric IS
l_date VARCHAR2(100);
BEGIN
l_date := TO_date( p_val, p_format );
RETURN 1;
EXCEPTION
WHEN OTHERS THEN
RETURN 0;
END is_valid_date;
BEGIN
DBMS_OUTPUT.PUT_LINE(is_valid_date('20120101', 'YYYYMMDD' ));
END;
but I get a generic error without any specific Oracle code, as if it is a syntax problem.
I need to check if a date is valid and, as there is no Oracle built in function for that, I have defined it inside my script (I don't want it to be global or stored somewhere).
Edit:
I have found a solution on an oracle forum using oracle regexp, instead of a function. My script is:
BEGIN
select * from mytable where not REGEXP_LIKE(mydatefield, '(((0[1-9]|[12]\d|3[01])\.(0[13578]|1[02])\.((19|[2-9]\d)\d{2}))|((0[1-9]|[12]\d|30)\.(0[13456789]|1[012])\.((19|[2-9]\d)\d{2}))|((0[1-9]|1\d|2[0-8])\.02\.((19|[2-9]\d)\d{2}))|(29\.02\.((1[6-9]|[2-9]\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00))))')
END;
where mydatefield is in the format DD.MM.YYYY

Answer 1

If that's your entire script, you're missing the DECLARE keyword at the start of your anonymous block:
DECLARE
FUNCTION is_valid_date (p_val in VARCHAR2, p_format IN VARCHAR2 )
RETURN numeric IS
l_date VARCHAR2(100);
BEGIN
l_date := TO_date( p_val, p_format );
RETURN 1;
EXCEPTION
WHEN OTHERS THEN
RETURN 0;
END is_valid_date;
BEGIN
DBMS_OUTPUT.PUT_LINE(is_valid_date('20120101', 'YYYYMMDD' ));
END;
/
anonymous block completed
1
Without that you'll get a series of errors starting with
Error starting at line : 1 in command -
FUNCTION is_valid_date (p_val in VARCHAR2, p_format IN VARCHAR2 )
Error report -
Unknown Command
... which I imagine is the 'generic error' you referred to.