Keeping History of PL/SQL code changes

-- Create a Table for logging the modifications
CREATE TABLE source_hist 
    AS SELECT SYSDATE change_date ,user_source.* 
        FROM user_source WHERE 1=2;

--Trigger for tracking the changes
CREATE OR REPLACE TRIGGER change_hist
AFTER CREATE ON scott.schema -- Change SCOTT to your schema name
DECLARE 
                BEGIN
                    IF DICTIONARY_OBJ_TYPE
  IN ('PROCEDURE','FUNCTION','PACKAGE','PACKAGE BODY','TYPE') THEN
                        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;