Oracle SQL procedure to check input length - sql

Question

I am trying to check the input length, to see if it's less than 7. It should show an error message, but the code below doesn't work. What's wrong with it?
CREATE OR REPLACE PROCEDURE prc_staffContact(IN_staffID IN CHAR, IN_staffContact IN VARCHAR) IS
v_staffName VARCHAR(50);
v_staffID CHAR(6);
v_staffContact VARCHAR(11);
BEGIN
SELECT s.staffName, s.staffID, s.staffContact
INTO v_staffName, v_staffID, v_staffContact
FROM staff s
WHERE staffID = IN_staffID;
IF (LENGTH(IN_staffContact) < 7 )
THEN
DBMS_OUTPUT.PUT_LINE('Error. Contact number at least 7 digits.');
ELSE
UPDATE staff
SET staffContact = IN_staffContact
WHERE staffID = IN_staffID;
DBMS_OUTPUT.PUT_LINE('=============================================================================');
DBMS_OUTPUT.PUT_LINE('The contact number of [ ' ||v_staffName || ' ] has been updated successfully.');
DBMS_OUTPUT.PUT_LINE('New contact number: [ ' ||v_staffContact || ' ].');
DBMS_OUTPUT.PUT_LINE('=============================================================================');
END IF;
END;
/

Answer 1

You said something that appears to be contradictory:
it shows [PL/SQL procedure successfully completed.] but doesn't checking even my input is less than 7 characters. and the data doesn't update also.
You described that you're doing as:
i save it under procedure1.sql and i start it in sql plus. that is my 1st call. after that i call the exec prc_staffContact('100001', '0000')
Together those suggest that when you say the data isn't updated, what you really mean is you don't get the contact number/new contact number message from the else branch, and I think you're assuming that means the update doesn't happen either, so it didn't execute either branch. But you must have gone into either the if or the else, by definition.
So if you didn't get either message, then you haven't done:
set serveroutput on
in SQL*Plus before calling exec. That setting is off by default, unless you have it turned on in your login.sql or glogin.sql, so you have to turn it on explicitly if you want to see dbms_output messages.
In this case, for the validation, (a) you probably want the select inside the elsef` too, partly because (b) if the passed values doesn't exist you'll get a no_data_found exception, and (c) you might want to consider throwing an exception if the length is less than 7 rather than (only) displaying a message. Someone else calling this might not have serverout on either, or might be using a different client that doesn't have that option.
You've also got v_staffID defined as char(6). Apart from wondering why that isn't a varchar2, the length you've given it means that if IN_staffID is 7 chars or more, the select into will get a 'character string buffer too small' error. I'd declare that as:
v_staffID staff.staffID%TYPE;
... to avoid issues like that, and the same for the other fields that relate to table columns.
And your 'success' message is showing the old contact number, not the new one. Not sure you need v_staffContact at all.

Answer 2

Look at your code carefully. May be your variable types not compatible or stored procedure parameters not compatible with other variables (or table columns, column's types). I tested your code in my database, all success. but may be error not data found in your select statement, or may be buffer too small error. Hope this help you. thanks