Oracle DDL Event Triggers

Oracle DDL Event Triggers Version 11.2.0.3

General Information

Data Dictionary Objects

ALL_TRIGGERS	TRIGGER$	USER_TRIGGERS
DBA_TRIGGERS

System Privileges

* Reqd. for ON DATABASE triggers

ADMINISTER DATABASE TRIGGER *	CREATE ANY TRIGGER	DROP TRIGGER
ALTER ANY TRIGGER	CREATE TRIGGER

Triggering Events

BEFORE / AFTER ALTER
BEFORE / AFTER ANALYZE
BEFORE / AFTER ASSOCIATE STATISTICS
BEFORE / AFTER AUDIT
BEFORE / AFTER COMMENT
BEFORE / AFTER CREATE
BEFORE / AFTER DDL
BEFORE / AFTER DISASSOCIATE STATISTICS
BEFORE / AFTER DROP
BEFORE / AFTER GRANT
BEFORE / AFTER NOAUDIT
BEFORE / AFTER RENAME
BEFORE / AFTER REVOKE
BEFORE / AFTER TRUNCATE
AFTER SUSPEND

Find Datbase Level Triggers

SELECT a.obj#, a.sys_evts, b.name
FROM trigger$ a,obj$ b
WHERE a.sys_evts > 0
AND a.obj#=b.obj#
AND baseobject = 0;

Find Schema Level Triggers

SELECT a.obj#, a.sys_evts, b.name
FROM trigger$ a,obj$ b
WHERE a.sys_evts > 0
AND a.obj#=b.obj#
AND baseobject = 88;

Demo Setup

Demo Privileges

-- user uwclass creation can be found on the SETUP page of the library

GRANT create session TO uwclass;
GRANT create procedure TO uwclass;
GRANT create sequence TO uwclass;
GRANT create table TO uwclass;
GRANT create trigger TO uwclass;
GRANT create view TO uwclass;

GRANT select ON gv_$open_cursor TO uwclass;

conn uwclass/uwclass

Table To Capture DDL Trigger Output

CREATE TABLE ddl_log (
operation   VARCHAR2(30),
obj_owner   VARCHAR2(30),
object_name VARCHAR2(30),
sql_text    VARCHAR2(64),
attempt_by VARCHAR2(30),
attempt_dt DATE);

DDL Triggers

Trigger To Log A Single DDL Activity On A Schema

CREATE OR REPLACE TRIGGER <trigger_name>
<BEFORE | AFTER> <triggering_action>
ON <SCHEMA | DATABASE>

DECLARE
-- variable declarations
BEGIN
-- trigger code
EXCEPTION
-- exception handler
END <trigger_name>;
/

CREATE OR REPLACE TRIGGER bcs_trigger
BEFORE CREATE
ON SCHEMA
BEGIN
INSERT INTO ddl_log
SELECT ora_sysevent, ora_dict_obj_owner, ora_dict_obj_name, NULL, USER, SYSDATE
FROM dual;
END bcs_trigger;
/

col object_name format a20

SELECT object_name, object_type
FROM user_objects;

col triggering_event format a20
SELECT trigger_name, trigger_type,
triggering_event, base_object_type
FROM user_triggers;

SELECT * FROM ddl_log;

CREATE SEQUENCE s1_test;

CREATE TABLE t1_test (
testcol VARCHAR2(20));

CREATE OR REPLACE VIEW v_test AS
SELECT * FROM t_test;

set linesize 151

SELECT operation, obj_owner, object_name
FROM ddl_log;

TRUNCATE TABLE ddl_log;

conn system/manager

CREATE TABLE uwclass.xyz (
testcol VARCHAR2(20));

conn uwclass/uwclass

SELECT operation, obj_owner, object_name
FROM ddl_log;

TRUNCATE TABLE ddl_log;

Trigger To Log A Single DDL Activity On The Database

conn system/manager

GRANT administer database trigger TO uwclass;

conn uwclass/uwclass

CREATE OR REPLACE TRIGGER bcd_trigger
BEFORE CREATE
ON DATABASE
BEGIN
INSERT INTO ddl_log
SELECT ora_sysevent, ora_dict_obj_owner, ora_dict_obj_name, NULL, USER, SYSDATE
FROM dual;
END bcd_trigger;
/

col object_name format a20
SELECT object_name, object_type
FROM user_objects;

col triggering_event format a20
SELECT trigger_name, trigger_type,
triggering_event, base_object_type
FROM user_triggers;

SELECT * FROM ddl_log;

CREATE SEQUENCE s2_test;

CREATE TABLE t2_test (
testcol VARCHAR2(20));

CREATE OR REPLACE VIEW v_test AS
SELECT * FROM t_test;

set linesize 150

SELECT operation, obj_owner, object_name
FROM ddl_log;

TRUNCATE TABLE ddl_log;

conn system/manager

CREATE TABLE uwclass.xyz (
testcol VARCHAR2(20));

conn uwclass/uwclass

SELECT operation, obj_owner, object_name
FROM ddl_log;

DROP TRIGGER bcd_trigger;

TRUNCATE TABLE ddl_log;

Trigger To Log Multiple DDL Activities

CREATE OR REPLACE TRIGGER <trigger_name>
<BEFORE | AFTER> <triggering_action> OR <trigger_action>
ON SCHEMA
DECLARE
-- variable declarations
BEGIN
-- trigger code
EXCEPTION
-- exception handlers
END <trigger_name>;
/

desc ddl_log

CREATE OR REPLACE TRIGGER ddl_trigger
BEFORE CREATE OR ALTER OR DROP
ON SCHEMA

DECLARE
oper ddl_log.operation%TYPE;
sql_text ora_name_list_t;
i        PLS_INTEGER;
BEGIN
SELECT ora_sysevent
INTO oper
FROM dual;

i := sql_txt(sql_text);

IF oper IN ('CREATE', 'DROP') THEN
    INSERT INTO ddl_log
    SELECT ora_sysevent, ora_dict_obj_owner,
    ora_dict_obj_name, sql_text(1), USER, SYSDATE
    FROM dual;
ELSIF oper = 'ALTER' THEN
    INSERT INTO ddl_log
    SELECT ora_sysevent, ora_dict_obj_owner,
    ora_dict_obj_name, sql_text(1), USER, SYSDATE
    FROM sys.gv_$sqltext
    WHERE UPPER(sql_text) LIKE 'ALTER%'
    AND UPPER(sql_text) LIKE '%NEW_TABLE%';
END IF;
END ddl_trigger;
/

col operation format a20
col obj_owner format a10

SELECT * FROM ddl_log;

conn / as sysdba

alter system flush shared_pool;
alter system flush shared_pool;

conn uwclass/uwclass

CREATE TABLE new_table (
charcol VARCHAR2(20));

SELECT * FROM ddl_log;

ALTER TABLE new_table
ADD (numbcol NUMBER(10));

SELECT * FROM ddl_log;

DROP TABLE new_table PURGE;

SELECT * FROM ddl_log;

TRUNCATE TABLE ddl_log;

Demo Triggers

DDL Trigger To Stop And Log Attempts To Drop Or Truncate

Requires the stored procedure below is created first

-- NOTE: Be sure to build the log_proc procedure (below) before trying to create this trigger

CREATE OR REPLACE TRIGGER save_our_db
BEFORE DROP OR TRUNCATE
ON SCHEMA
DECLARE
oper ddl_log.operation%TYPE;
BEGIN
oper := ora_sysevent;
log_proc(ora_sysevent, ora_dict_obj_owner, ora_dict_obj_name);

IF oper = 'DROP' THEN
    RAISE_APPLICATION_ERROR(-20998, 'Attempt To Drop
    In Production Has Been Logged');
ELSIF oper = 'TRUNCATE' THEN
    RAISE_APPLICATION_ERROR(-20999, 'Attempt To Truncate A
    Production Table Has Been Logged');
END IF;
END save_our_db;
/

SELECT * FROM ddl_log;

DROP TRIGGER ddl_trigger;

SELECT * FROM ddl_log;

ALTER TRIGGER save_our_db DISABLE;

DROP TRIGGER ddl_trigger;

SELECT * FROM ddl_log;

TRUNCATE TABLE ddl_log;

SELECT * FROM ddl_log;

ALTER TRIGGER save_our_db ENABLE;

DROP VIEW v_test;

SELECT * FROM ddl_log;

SELECT object_name FROM user_objects;

DROP SEQUENCE v1_test;

SELECT * FROM ddl_log;

SELECT object_name FROM user_objects;

DROP TRIGGER save_our_db;

TRUNCATE TABLE ddl_log;

Logging Procedure

CREATE OR REPLACE PROCEDURE log_proc (
ose ddl_log.operation%TYPE,
odoo ddl_log.obj_owner%TYPE,
odon ddl_log.object_name%TYPE)
IS
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
INSERT INTO ddl_log
SELECT ora_sysevent, ora_dict_obj_owner,
ora_dict_obj_name, 'Not Allowed', USER, SYSDATE
FROM dual;
COMMIT;
END log_proc;
/

DDL Trigger To Prevent Creating Objects That Whose Names Begin With The Letter 'X'

CREATE OR REPLACE TRIGGER no_xtabs
BEFORE CREATE
ON SCHEMA
DECLARE
x user_tables.table_name%TYPE;
BEGIN
SELECT ora_dict_obj_name
INTO x
FROM dual;

IF SUBSTR(x, 1, 1) = 'X' THEN
RAISE_APPLICATION_ERROR(-20099, 'Table Names Can Not Start With The Letter X');
END IF;
END no_xtabs;
/

CREATE TABLE ztest (
testcol VARCHAR2(20));

CREATE TABLE xtest (
testcol VARCHAR2(20));

Demo of an application that identifies and logs all DDL

conn / as sysdba

CREATE TABLESPACE logging
DATAFILE 'c:\temp\logtsp01.dbf' SIZE 100M
EXTENT MANAGEMENT LOCAL
UNIFORM SIZE 64K;

CREATE USER loguser
IDENTIFIED BY loguser
DEFAULT TABLESPACE logging
TEMPORARY TABLESPACE temp
QUOTA 0 ON SYSTEM
QUOTA UNLIMITED ON logging;

-- note that no system privileges have been granted the table is being built by SYS

CREATE TABLE loguser.ddl_log (
user_name     VARCHAR2(30),
ddl_date      DATE,
ddl_type      VARCHAR2(30),
object_type   VARCHAR2(18),
owner         VARCHAR2(30),
object_name   VARCHAR2(128))
TABLESPACE logging;

CREATE OR REPLACE TRIGGER ddl_trig
AFTER DDL
ON DATABASE
BEGIN
INSERT INTO loguser.ddl_log
(user_name, ddl_date, ddl_type,
   object_type, owner,
   object_name)
VALUES
(ora_login_user, SYSDATE, ora_sysevent,
   ora_dict_obj_type, ora_dict_obj_owner,
   ora_dict_obj_name);
END ddl_trig;
/

conn uwclass/uwclass

CREATE TABLE t3_test (
testcol DATE);

conn / as sysdba

SELECT * FROM loguser.ddl_log;

Disable granting privileges to PUBLIC

GRANT ALL ON servers TO SCOTT;
GRANT ALL ON servers TO PUBLIC;
REVOKE ALL ON servers FROM SCOTT;
REVOKE ALL ON servers FROM PUBLIC;

CREATE OR REPLACE TRIGGER ddl_trig
BEFORE GRANT
ON DATABASE
DECLARE
g_list dbms_standard.ora_name_list_t;
n      PLS_INTEGER;
BEGIN
n := ora_grantee(g_list);
FOR i IN 1..n LOOP
IF g_list(i) = 'PUBLIC' THEN
    RAISE_APPLICATION_ERROR(-20997,'Public Grants Not Allowed');
    END IF;
END LOOP;
END;
/

set serveroutput on

GRANT ALL ON servers TO SCOTT;
GRANT ALL ON servers TO PUBLIC;
REVOKE ALL ON servers FROM SCOTT;
REVOKE ALL ON servers FROM PUBLIC;