SQL How to handle an exception in user defined functions? - sql

Question

CREATE OR REPLACE Function fun_Find_Staff_Name( v_staffid IN NUMBER )
RETURN VARCHAR2
IS
staff_name VARCHAR2(60);
CURSOR c_staff IS
SELECT staff_firstName || ' ' || staff_lastName
into staff_name
FROM staff
WHERE staff_id = v_staffid;
BEGIN
OPEN c_staff;
FETCH c_staff INTO staff_name;
CLOSE c_staff;
RETURN staff_name;
END;
This function takes a staff_id and returns the corresponding staff name. I want to handle the exception if the user enters an ID that is invalid and display an error message? Where do I add the exception block?
SET serveroutput ON;
DECLARE
v_staff_ID NUMBER := &StaffID;
v_message VARCHAR2(100);
BEGIN
v_message := fun_Find_Staff_Name(v_staff_ID);
dbms_output.put_line(v_message);
END;
I used this anonyomus block to check if the function works properly.

Answer 1

In my opinion you don't need an explicit cursor, an embedded sql will do the trick:
CREATE OR REPLACE Function fun_Find_Staff_Name
( v_staffid IN NUMBER )
RETURN VARCHAR2
IS
staff_name VARCHAR2(60);
BEGIN
SELECT staff_firstName || ' ' || staff_lastName
INTO staff_name
FROM staff WHERE staff_id = v_staffid;
RETURN staff_name;
EXCEPTION
WHEN NO_DATA_FOUND THEN
--in case of an invalid id no data will be found
--you can treat your exception here
--example
DBMS_OUTPUT.PUT_LINE('No data found for this id: ' || v_staffid);
RAISE;
WHEN OTHERS THEN
RAISE;
END fun_Find_Staff_Name ;
And please remember that when you are handling exceptions don't forget to raise it; if not the database will not rollback the transaction in case of an error.
If it yells some errors at the compilation, I am sorry, but I wrote the code without compiling it (in a hurry from my mob).
Cheers and happy coding.