Migrating 7.3.4 to 8.1.7 - whitespace? issue

Question

We are migrating 7.3.4 to 8.1.7. We are aware of the need to ltrim/rtrim varchars, etc. I am looking for the Oracle documentation of the change that requires these changes. Can anyone point me to the text of this change? Is the migration guide on-line?
thanks.

Answer 1

found the original document on this bug fix -
WebIV:View NOTE:130132.1     
Article-ID: <Note:130132.1>
Circulation: REVIEW_CHANGES (EXTERNAL)
Folder: PLSQL
Topic: Problem and Solution Articles
Title: ORA-06502 Encountered When Converting Character to Number
Open-Remarks: See <RemarksOn:NOTE:130132.1>
Document-Type: PROBLEM
Impact: MEDIUM
Skill-Level: ACCOMPLISHED
Updated-Date: 04-APR-2001 15:08:15
References: <<BUG:571545>>
Shared-Refs:
Authors: MMCLAUGH.US
Attachments: NONE
Content-Type: TEXT/PLAIN
Products: 11/PLSQL;
Platforms: GENERIC;
This article is being delivered in Draft form and may contain
errors. Please use the MetaLink "Feedback" button to advise
Oracle of any issues related to this article.
Problem Description
You have just upgraded from Oracle7 or Oracle8 to Oracle8i (8.1.6 or higher)
and your PL/SQL code is failing with the following error:
Error Messages:
Potential Error #1:
ORA-06502: PL/SQL: numeric or value error: character to number conversion error
ORA-06512: at line 46
Potential Error #2:
ORA-01722: invalid number
Sample Code to Generate the Error
-- Enable serverout to display DBMS_OUTPUT package calls.
SET SERVEROUTPUT ON SIZE 1000000
-- Drop test table.
DROP TABLE caste;
-- Create test table to support example program cursor.
CREATE TABLE caste (variable_number NUMBER);
-- Insert one row into the test table.
INSERT INTO caste VALUES (1);
-- An anonymous block PL/SQL program to test problem.
-- The program works in releases prior to Oracle8i (8.1.6).
DECLARE
|| Declare a VARCHAR2 datatype and initialize it with a whitespace
|| and a NUMBER datatype to store output of a NUMBER datatype
|| stored in the database.
var_in VARCHAR2(30) := ' ';
var_out NUMBER;
|| Declare a cursor that accepts a NUMBER datatype as a parameter.
CURSOR testing (var_in NUMBER) IS
SELECT NVL(variable_number,8) value_in
FROM caste
WHERE variable_number = var_in;
BEGIN
|| Display counts of the var_in variable as a whitespace.
DBMS_OUTPUT.PUT_LINE('var_char <'||var_in||'>');
|| Declare a FOR-LOOP and pass the VARCHAR2 datatype with a whitespace
|| into the CURSOR testing that is defined as accepting a NUMBER
|| datatype.
FOR i IN testing (var_in) LOOP
var_out := i.value_in;
END LOOP;
DBMS_OUTPUT.PUT_LINE('var_out is <'||var_out||'>');
END;
Sample code output in Oracle7 and Oracle8:
var_char < >
var_out is <>
Sample code output in Oracle8i (8.1.6 or newer):
DECLARE
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character to number conversion error
ORA-06512: at line 35
Solution Description
1. Rewrite all code to pass a null, or '' value into a VARCHAR2 datatype
that will pass a value to a NUMBER datatype.
2. Redesign your PL/SQL programs so that strong datatyping principles
are used and do not pass VARCHAR2 datatype by design into NUMBER
type by implicit casting, use explicit casting with the TO_NUMBER()
and TO_CHAR() functions, as described in Chapter 2 of the PL/SQL
User's Guide for versions newer than PL/SQL 2.0.
3. If your intent is to caste a VARCHAR2 null to a zero, then you can
use the following assignment to a NUMBER datatype variable named
"p_converted" from a VARCHAR2 datatype name "p_unconverted":
p_converted := TO_NUMBER(NVL(p_unconverted,0));
Explanation
Prior to Oracle8i (8.1.6), you could assign a whitespace in a VARCHAR2 datatype
to a NUMBER datatype without encountering an error because the whitespace would
be implicitly caste to a null. Unfortunately, the behavior that allowed this
implicit caste caused a TO_NUMBER() function call to return a zero instead of
raise an "ORA-01722: invalid number" error, as described in <BUG:571545>.
Therefore, customers upgrading from Oracle7 or Oracle8 to Oracle8i will find
that code that previously did not raise an exception will now raise and
exception becasue passing a VARCHAR2 datatype with a whitespace value into a
NUMBER datatype is in appropriate and calling the TO_NUMBER() function to
return a zero from a whitespace is incorrect.
References
<Bug:571545