Capture error using OUT parameter in Oracle's procedure - oracle

Question

I have to create procedure to insert row into table, also I need to include am OUT parameter that would capture any errors. However when I test using anonymous block it would not work, but if I use exception in procedure it is working. It means if I add an OUT parameter and I pass values from the block it won't work.
This code works but is not what I want:
create or replace
PROCEDURE EXAM_SP
(P_FIRSTNAME IN BB_SHOPPER.FIRSTNAME%TYPE,
P_LASTNAME IN BB_SHOPPER.LASTNAME%TYPE,
P_ADDRESS IN BB_SHOPPER.ADDRESS%TYPE,
P_CITY IN BB_SHOPPER.CITY%TYPE,
P_STATE IN BB_SHOPPER.STATE%TYPE,
P_ZIP IN BB_SHOPPER.ZIPCODE%TYPE)
IS
BEGIN
INSERT INTO BB_SHOPPER (IDSHOPPER, FIRSTNAME, LASTNAME, ADDRESS, CITY,
STATE, ZIPCODE)
VALUES
(BB_SHOPPER_IDSHOPPER_SEQ.NEXTVAL,P_FIRSTNAME,P_LASTNAME,P_ADDRESS,
P_CITY, P_STATE,P_ZIP);
EXCEPTION
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE('Error Code = '||SQLCODE);
DBMS_OUTPUT.PUT_LINE('Error Message = Please check input');
END EXAM_SP;.
But in code above if I name out parameter it won't work, not sure how to do this, if I add OUT parameter to procedure and pass values:
create or replace
PROCEDURE EXAM_SP
(P_FIRSTNAME IN VARCHAR2,
P_LASTNAME IN VARCHAR2,
P_ADDRESS IN VARCHAR2,
P_CITY IN VARCHAR2,
P_STATE IN CHAR,
P_ZIP IN VARCHAR2,
P_ERROR OUT VARCHAR2)......
I will receive this error
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
If I remove parameter and use original code on the beginning it works.
Anonymous block that gets that error:
DECLARE
LV_FIRSTNAME_TXT BB_SHOPPER.FIRSTNAME%TYPE := 'FIRST';
LV_LASTNAME_TXT BB_SHOPPER.LASTNAME%TYPE := 'LAST';
LV_ADDRESS_TXT BB_SHOPPER.ADDRESS%TYPE := '8899 TAPE PARK';
LV_CITY_TXT BB_SHOPPER.CITY%TYPE := 'JACKSONVILLE';
LV_STATE_TXT BB_SHOPPER.STATE%TYPE := 'FLd';
LV_ZIP_NUMBER BB_SHOPPER.ZIPCODE%TYPE := '34567';
LV_ERROR varchar2(100);
BEGIN
EXAM_SP(LV_FIRSTNAME_TXT, LV_LASTNAME_TXT, LV_ADDRESS_TXT,
LV_CITY_TXT,LV_STATE_TXT,LV_ZIP_NUMBER);
DBMS_OUTPUT.PUT_LINE(LV_ERROR);
END;
Procedure:
create or replace
PROCEDURE EXAM_SP
(P_FIRSTNAME IN VARCHAR2,
P_LASTNAME IN VARCHAR2,
P_ADDRESS IN VARCHAR2,
P_CITY IN VARCHAR2,
P_STATE IN CHAR,
P_ZIP IN VARCHAR2,
P_ERROR OUT VARCHAR2)
IS
BEGIN
INSERT INTO BB_SHOPPER (IDSHOPPER, FIRSTNAME, LASTNAME, ADDRESS, CITY,
STATE, ZIPCODE)
VALUES
(BB_SHOPPER_IDSHOPPER_SEQ.NEXTVAL,P_FIRSTNAME,P_LASTNAME,P_ADDRESS,
P_CITY, P_STATE,P_ZIP);
EXCEPTION
WHEN OTHERS THEN
P_ERROR := SQLCODE;
/*DBMS_OUTPUT.PUT_LINE('Error Code = '||SQLCODE);
DBMS_OUTPUT.PUT_LINE('Error Message = Please check input');
P_ERROR := SQLCODE;*/
END EXAM_SP;
Error message that I am receiving:
Error report:
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at line 6
06502. 00000 - "PL/SQL: numeric or value error%s"
I have passed variable 'FLd' to procedure parameter in order to test error capture.
Table structure:
IDSHOPPER NUMBER(4,0)
FIRSTNAME VARCHAR2(15 BYTE)
LASTNAME VARCHAR2(20 BYTE)
ADDRESS VARCHAR2(40 BYTE)
CITY VARCHAR2(20 BYTE)
STATE CHAR(2 BYTE)
ZIPCODE VARCHAR2(15 BYTE)
PHONE VARCHAR2(10 BYTE)
FAX VARCHAR2(10 BYTE)
EMAIL VARCHAR2(25 BYTE)
USERNAME VARCHAR2(8 BYTE)
PASSWORD VARCHAR2(8 BYTE)
COOKIE NUMBER(4,0)
DTENTERED DATE
PROVINCE VARCHAR2(15 BYTE)
COUNTRY VARCHAR2(15 BYTE)
...

Answer 1

"If I add out parameter to procedure and I pass values I will receive this error"
Alex has provided the long answer, I'm just going to make one short point: this is bad practice. Most programming languages include built-in functionality for handling exceptions. What you propose creates two architectural problems:
Programs which call your procedure have to write non-standard code to catch errors, which is just a pain for both the developers who write the calling programs and everybody else who has to understand how they work.
Your procedure doesn't hurl an exception so even though it "failed" it returns a success state to calling programs. If the developer who wrote the calling program didn't implement the special code the exception is lost and the database can be left in an invalid state.

Answer 2

The error stack shows:
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at line 6
06502. 00000 - "PL/SQL: numeric or value error%s"
That stack shows, partly because it doesn't mention the procedure name, that the error is from line 6 of the anonymous block. It isn't getting as far as the call to the procedure on line 11 of that block.
The problem is that you've defined the local state variable:
LV_STATE_TXT BB_SHOPPER.STATE%TYPE := 'FLd';
using the %TYPE syntax, which is great; but as the table column is char(2), when you try to assign the three-character text literal 'Fld' to that two-character local variable it immediately errors at that point.
it is not getting as far as sending the three-character value to the procedure, so the error you're expecting from the insert doesn't appear because the insert doesn't happen either.
If you want to break it with that particular error you can either change the local variable declaration to be a fixed length instead of using %TYPE as you would normally want to:
DECLARE
LV_FIRSTNAME_TXT BB_SHOPPER.FIRSTNAME%TYPE := 'FIRST';
LV_LASTNAME_TXT BB_SHOPPER.LASTNAME%TYPE := 'LAST';
LV_ADDRESS_TXT BB_SHOPPER.ADDRESS%TYPE := '8899 TAPE PARK';
LV_CITY_TXT BB_SHOPPER.CITY%TYPE := 'JACKSONVILLE';
--LV_STATE_TXT BB_SHOPPER.STATE%TYPE := 'FLd';
-- specific length to allow invalid value to be used
LV_STATE_TXT char(3) := 'FLd';
LV_ZIP_NUMBER BB_SHOPPER.ZIPCODE%TYPE := '34567';
LV_ERROR varchar2(100);
BEGIN
EXAM_SP(LV_FIRSTNAME_TXT, LV_LASTNAME_TXT, LV_ADDRESS_TXT,
LV_CITY_TXT,LV_STATE_TXT,LV_ZIP_NUMBER,LV_ERROR);
DBMS_OUTPUT.PUT_LINE(LV_ERROR);
END;
/
-12899
PL/SQL procedure successfully completed.
Or more simply use literals directly for the IN parameters, as you are just testing the procedure at this point:
DECLARE
LV_ERROR varchar2(100);
BEGIN
EXAM_SP('FIRST', 'LAST', '8899 TAPE PARK',
'JACKSONVILLE', 'FLd', '34567', LV_ERROR);
DBMS_OUTPUT.PUT_LINE(LV_ERROR);
END;
/
-12899
PL/SQL procedure successfully completed.
You might find it more useful to return the error text, not just the number (and if you're returning the error number use a numeric formal argument type!), e.g:
...
EXCEPTION
WHEN OTHERS THEN
P_ERROR := SQLERRM;
END EXAM_SP;
/
-- same anonymous block
ORA-12899: value too large for column "MY_SCHEMA"."BB_SHOPPER"."STATE" (actual: 3, maximum: 2)
PL/SQL procedure successfully completed.
Of course, as I mentioned in a comment, it's better to let Oracle's exception handling just bubble the actual exception up to the caller - aside maybe from logging, you should only really catch exceptions you can actually handle. Notice that the error message that's passed back doesn't tell you anything about where the error occurred in the code; without the exception handler you would see the line number in the procedure that had the offending statement. And as APC points out, every caller has to look for and handle the resposne, and it would be easy to overlook. There are always exceptions (ha) of course, but this seems to be an exercise in doing things wrong.