create audit trail using oracle trigger - oracle

Question

I am trying to create a trigger that will audit all new and old columns or each row updated, inserted. here is the table
ID NUMBER(10,0) No 1
ENTITY_ID NUMBER(10,0) No 2
LOCATION_ID NUMBER(10,0) Yes 3
NAME VARCHAR2(128 CHAR) No 4
CREATED_BY VARCHAR2(255 CHAR) No 'unknown' 5
UPDATED_BY VARCHAR2(255 CHAR) No 'unknown' 6
TS_CREATED TIMESTAMP(6) No "SYSTIMESTAMP
" 7
I am not sure how to write the trigger.
CREATE OR REPLACE TRIGGER audit_security_zones
BEFORE DELETE OR INSERT OR UPDATE ON security_zones
FOR EACH ROW
DECLARE
BEGIN
END;
I also want to use client identifier senbt from application. Here is my audit trail table.
ID NUMBER(10,0) No 1
ACTION VARCHAR2(20 BYTE) Yes 2
TABLE_ID VARCHAR2(100 BYTE) Yes 3
OLD_VALUE VARCHAR2(1000 BYTE) Yes 4
NEW_VALUE VARCHAR2(1000 BYTE) Yes 5
USERNAME VARCHAR2(100 BYTE) Yes 6
TS_UPDATED TIMESTAMP(6) No systimestamp 7
Is this a good way to do this? I will then render a view for the user based on each table to show them what has changed.
UPDATE
I am trying to achieve something similar to the following
CREATE OR REPLACE TRIGGER audit_security_zones
BEFORE DELETE OR INSERT OR UPDATE ON security_zones
FOR EACH ROW
DECLARE
var_action CHAR(1);
BEGIN
IF INSERTING THEN var_action := 'INSERT';
ELSIF UPDATING THEN var_action := 'UPDATE';
ELSE var_action := 'DELETE';
END IF;
/* loop eahc column in the update or insert or delete statement executed */
for each col in stmt/row{
INSERT INTO audit_table
(
ACTION,
TABLE_ID,
OLD_VALUE,
NEW_VALUE,
USERNAME,
TS_CREATED
) VALUES (
var_action,
:OLD.ID,
:OLD.columnVALUE,
:new.COLUMNVALUE,
ociidentifier,
systimestamp
)
}
END;
UPDATE2
CREATE OR REPLACE TRIGGER audit_security_zones
BEFORE DELETE OR INSERT OR UPDATE ON security_zones
FOR EACH ROW
DECLARE
var_action CHAR(6);
BEGIN
IF INSERTING THEN var_action := 'INSERT';
ELSIF UPDATING THEN var_action := 'UPDATE';
ELSE var_action := 'DELETE';
END IF;
IF var_action = 'DELETE' THEN
INSERT INTO audit_table
(
ACTION,
USERNAME,
ID,
O_ENTITY_ID,
O_LOCATION_ID,
O_NAME,
O_CREATED_BY,
O_UPDATED_BY,
O_TS_CREATED
) VALUES (
var_action,
USERNAME,
:OLD.ID,
:OLD.ENTITY_ID,
:OLD.LOCATION_ID,
:OLD.NAME,
:OLD.CREATED_BY,
:OLD.UPDATED_BY,
:OLD.TS_CREATED
);
ELSEIF var_action = 'INSERT' THEN
INSERT INTO audit_table
(
ACTION,
USERNAME,
ID,
N_ENTITY_ID,
N_LOCATION_ID,
N_NAME,
N_CREATED_BY,
N_UPDATED_BY
N_TS_CREATED
) VALUES (
var_action,
USERNAME,
:NEW.ID,
:NEW.ENTITY_ID,
:NEW.LOCATION_ID,
:NEW.NAME,
:NEW.CREATED_BY,
:NEW.UPDATED_BY,
:NEW.TS_CREATED
);
ELSEIF var_action = 'UPDATE' THEN
INSERT INTO audit_table
(
ACTION,
USERNAME,
ID,
O_ENTITY_ID,
O_LOCATION_ID,
O_NAME,
O_CREATED_BY,
O_UPDATED_BY,
O_TS_CREATED,
N_ENTITY_ID,
N_LOCATION_ID,
N_NAME,
N_CREATED_BY,
N_UPDATED_BY
N_TS_CREATED
) VALUES (
var_action,
USERNAME,
:OLD.ID,
:OLD.ENTITY_ID,
:OLD.LOCATION_ID,
:OLD.NAME,
:OLD.CREATED_BY,
:OLD.UPDATED_BY,
:OLD.TS_CREATED,
:NEW.ENTITY_ID,
:NEW.LOCATION_ID,
:NEW.NAME,
:NEW.CREATED_BY,
:NEW.UPDATED_BY,
:NEW.TS_CREATED
);
END IF;
END;
I get the following errors
Error(31,9): PLS-00103: Encountered the symbol "VAR_ACTION" when expecting one of the following: := . ( # % ;
Error(42,4): PLS-00103: Encountered the symbol "N_TS_CREATED" when expecting one of the following: . ) , # The symbol "." was substituted for "N_TS_CREATED" to continue.
Error(54,12): PLS-00103: Encountered the symbol "VAR_ACTION" when expecting one of the following: := . ( # % ;
Error(71,4): PLS-00103: Encountered the symbol "N_TS_CREATED" when expecting one of the following: . ) , # The symbol "." was substituted for "N_TS_CREATED" to continue.
Error(90,4): PLS-00103: Encountered the symbol ";" when expecting one of the following: if
UPDATE3
CREATE OR REPLACE TRIGGER audit_security_zones
BEFORE DELETE OR INSERT OR UPDATE ON security_zones
FOR EACH ROW
DECLARE
var_action CHAR(6);
BEGIN
IF INSERTING THEN var_action := 'INSERT';
ELSIF UPDATING THEN var_action := 'UPDATE';
ELSE var_action := 'DELETE';
END IF;
IF var_action = 'DELETE' THEN
INSERT INTO audit_table
(
ACTION,
USERNAME,
ID,
O_ENTITY_ID,
O_LOCATION_ID,
O_NAME,
O_CREATED_BY,
O_UPDATED_BY,
O_TS_CREATED
) VALUES (
var_action,
USERNAME,
:OLD.ID,
:OLD.ENTITY_ID,
:OLD.LOCATION_ID,
:OLD.NAME,
:OLD.CREATED_BY,
:OLD.UPDATED_BY,
:OLD.TS_CREATED
);
ELSE IF var_action = 'INSERT' THEN
INSERT INTO audit_table
(
ACTION,
USERNAME,
ID,
N_ENTITY_ID,
N_LOCATION_ID,
N_NAME,
N_CREATED_BY,
N_UPDATED_BY,
N_TS_CREATED
) VALUES (
var_action,
USERNAME,
:NEW.ID,
:NEW.ENTITY_ID,
:NEW.LOCATION_ID,
:NEW.NAME,
:NEW.CREATED_BY,
:NEW.UPDATED_BY,
:NEW.TS_CREATED
);
ELSE IF var_action = 'UPDATE' THEN
INSERT INTO audit_table
(
ACTION,
USERNAME,
ID,
O_ENTITY_ID,
O_LOCATION_ID,
O_NAME,
O_CREATED_BY,
O_UPDATED_BY,
O_TS_CREATED,
N_ENTITY_ID,
N_LOCATION_ID,
N_NAME,
N_CREATED_BY,
N_UPDATED_BY,
N_TS_CREATED
) VALUES (
var_action,
USERNAME,
:OLD.ID,
:OLD.ENTITY_ID,
:OLD.LOCATION_ID,
:OLD.NAME,
:OLD.CREATED_BY,
:OLD.UPDATED_BY,
:OLD.TS_CREATED,
:NEW.ENTITY_ID,
:NEW.LOCATION_ID,
:NEW.NAME,
:NEW.CREATED_BY,
:NEW.UPDATED_BY,
:NEW.TS_CREATED
);
END IF;
END;
error i get now is
Error(90,4): PLS-00103: Encountered the symbol ";" when expecting one of the following: if
UPDATE4
CREATE OR REPLACE TRIGGER audit_security_zones
BEFORE DELETE OR INSERT OR UPDATE ON security_zones
FOR EACH ROW
DECLARE
var_action CHAR(6);
BEGIN
IF INSERTING THEN var_action := 'INSERT';
ELSIF UPDATING THEN var_action := 'UPDATE';
ELSE var_action := 'DELETE';
END IF;
IF var_action = 'DELETE' THEN
INSERT INTO audit_table
(
ACTION,
USERNAME,
ID,
O_ENTITY_ID,
O_LOCATION_ID,
O_NAME,
O_CREATED_BY,
O_UPDATED_BY,
O_TS_CREATED
) VALUES (
var_action,
'test',
:OLD.ID,
:OLD.ENTITY_ID,
:OLD.LOCATION_ID,
:OLD.NAME,
:OLD.CREATED_BY,
:OLD.UPDATED_BY,
:OLD.TS_CREATED
);
ELSIF var_action = 'INSERT' THEN
INSERT INTO audit_table
(
ACTION,
USERNAME,
ID,
N_ENTITY_ID,
N_LOCATION_ID,
N_NAME,
N_CREATED_BY,
N_UPDATED_BY,
N_TS_CREATED
) VALUES (
var_action,
'test',
:NEW.ID,
:NEW.ENTITY_ID,
:NEW.LOCATION_ID,
:NEW.NAME,
:NEW.CREATED_BY,
:NEW.UPDATED_BY,
:NEW.TS_CREATED
);
ELSIF var_action = 'UPDATE' THEN
INSERT INTO audit_table
(
ACTION,
USERNAME,
ID,
O_ENTITY_ID,
O_LOCATION_ID,
O_NAME,
O_CREATED_BY,
O_UPDATED_BY,
O_TS_CREATED,
N_ENTITY_ID,
N_LOCATION_ID,
N_NAME,
N_CREATED_BY,
N_UPDATED_BY,
N_TS_CREATED
) VALUES (
var_action,
'test',
:OLD.ID,
:OLD.ENTITY_ID,
:OLD.LOCATION_ID,
:OLD.NAME,
:OLD.CREATED_BY,
:OLD.UPDATED_BY,
:OLD.TS_CREATED,
:NEW.ENTITY_ID,
:NEW.LOCATION_ID,
:NEW.NAME,
:NEW.CREATED_BY,
:NEW.UPDATED_BY,
:NEW.TS_CREATED
);
END IF;
END;
new error i get
Error(9,3): PL/SQL: SQL Statement ignored
Error(19,4): PL/SQL: ORA-00904: "O_TS_CREATED": invalid identifier
Error(32,3): PL/SQL: SQL Statement ignored
Error(42,4): PL/SQL: ORA-00904: "N_TS_CREATED": invalid identifier
Error(55,9): PL/SQL: SQL Statement ignored
Error(71,4): PL/SQL: ORA-00904: "N_TS_CREATED": invalid identifier

Answer 1

You cannot "loop" through the OLD and NEW values, you have to reference each one explicitly i.e.
INSERT INTO audit_table
(
ACTION,
TABLE_ID,
OLD_VALUE,
NEW_VALUE,
USERNAME,
TS_CREATED
) VALUES (
var_action,
:OLD.ID,
:OLD.column1VALUE,
:new.COLUMN1VALUE,
ociidentifier,
systimestamp
);
INSERT INTO audit_table
(
ACTION,
TABLE_ID,
OLD_VALUE,
NEW_VALUE,
USERNAME,
TS_CREATED
) VALUES (
var_action,
:OLD.ID,
:OLD.column2VALUE,
:new.COLUMN2VALUE,
ociidentifier,
systimestamp
);
... etc.
You may be able to simplify the code somewhat by writing a procedure to wrap the INSERT statement and calling that many times instead of the INSERT statement itself.