How can one see if somebody modified any code in pl sql?

Answer 1

The source code for stored procedures, functions and packages are stored in the Oracle Data Dictionary. One can detect code changes by looking at the TIMESTAMP and LAST_DDL_TIME column in the USER_OBJECTS dictionary view. Example:

SELECT OBJECT_NAME,
       TO_CHAR(CREATED,       'DD-Mon-RR HH24:MI') CREATE_TIME,
       TO_CHAR(LAST_DDL_TIME, 'DD-Mon-RR HH24:MI') MOD_TIME,
       STATUS
FROM   USER_OBJECTS
WHERE  LAST_DDL_TIME > '&CHECK_FROM_DATE';

Note: If you recompile an object, the LAST_DDL_TIME column is updated, but the TIMESTAMP column is not updated. If you modified the code, both the TIMESTAMP and LAST_DDL_TIME columns are updated.

Source: http://www.orafaq.com/wiki/PL/SQL_FAQ#How_can_one_see_if_somebody_modified_any_code.3F