How can you Track the modifications done to DB objects

SELECT object_name AS "Object Name",
object_type AS "Object Type",
status AS "Status",
created AS "Created",
last_ddl_time AS "Last Modified"
FROM user_objects
WHERE last_ddl_time >= :p_check_date


The above query will retrieve all the object(s) modified on or after the date provided (p_check_date)