How can one keep a history of PL/SQL code changes?

Question

Hello All,
I am trying to execute the following code found at
http://www.orafaq.com/faqplsql.htm#HIST
CREATE OR REPLACE TRIGGER change_hist -- Store code in hist table
AFTER CREATE ON OPERADWOWNER.SCHEMA -- Change SCOTT to your schema name
DECLARE
BEGIN
if DICTIONARY_OBJ_TYPE in ('PROCEDURE', 'FUNCTION',
'PACKAGE', 'PACKAGE BODY', 'TYPE') then
-- Store old code in SOURCE_HIST table
INSERT INTO SOURCE_HIST
SELECT sysdate, user_source.* FROM USER_SOURCE
WHERE TYPE = DICTIONARY_OBJ_TYPE
AND NAME = DICTIONARY_OBJ_NAME;
end if;
EXCEPTION
WHEN OTHERS THEN
raise_application_error(-20000, SQLERRM);
END;
It is giving the error
6/14 PL/SQL: SQL Statement ignored
9/31 PL/SQL: ORA-00904: "DICTIONARY_OBJ_NAME": invalid identifier
I want to understand what is DICTIONARY_OBJ_NAME in the above given code.
Regards

Answer 1

It's supposed to be ora_dict_obj_type. This is one of many event attributes that we can interrogate in DDL triggers. You can find out more in the online docs.
Cheers, APC