How to insert data into table even if trigger fails? - sql

Question

Oracle 11.1
I have custom logging table where I insert data:
CREATE TABLE log_table
(
message VARCHAR2(255),
created_by VARCHAR2(40) NOT NULL,
created_at DATE NOT NULL,
);
I have a trigger that runs on a specific table which does some checkings. My problem is: when the trigger fails, I want to be able to log some data into the log_table.
Trigger:
CREATE OR REPLACE TRIGGER my_trigger
FOR INSERT OR UPDATE OF column
ON my_table
COMPOUND TRIGGER
BEFORE STATEMENT IS
BEGIN
// code
END BEFORE STATEMENT;
BEFORE EACH ROW IS
BEGIN
IF (/*condition for failing*/) THEN
EXECUTE IMMEDIATE 'INSERT INTO mesaj_ama VALUES (:my_message, :my_user, :my_data)'
USING 'custom error message', SYS.LOGIN_USER, SYSDATE;
RAISE_APPLICATION_ERROR(-20001, 'some error');
END IF;
END BEFORE EACH ROW;
END my_trigger;
/
The following code doesn't work. I tried to use EXECUTE IMMEDIATE maybe to force it, but didn't work. I know that in case of an error, there is automatically a table rollback (which means that the INSERT command is cancelled), but I need a way to do this. Any help?

Answer 1

The concept you're looking for is an Autonomous Trasnaction, eg
CREATE OR REPLACE TRIGGER log_sal
BEFORE UPDATE OF salary ON emp FOR EACH ROW
DECLARE
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
INSERT INTO log (
log_id,
up_date,
new_sal,
old_sal
)
VALUES (
:old.employee_id,
SYSDATE,
:new.salary,
:old.salary
);
COMMIT;
END;

Answer 2

Yes, PRAGMA AUTONOMOUS_TRANSACTION seems to be the answer. Here is the working code:
Defined a procedure for logging:
CREATE OR REPLACE PROCEDURE log_error(p_error log_table.message % TYPE) AS
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
INSERT INTO log_table
VALUES (p_error, SYS.LOGIN_USER, SYSDATE);
COMMIT;
END;
and the trigger which calls the procedure:
CREATE OR REPLACE TRIGGER my_trigger
FOR INSERT OR UPDATE OF column
ON my_table
COMPOUND TRIGGER
BEFORE STATEMENT IS
BEGIN
// code
END BEFORE STATEMENT;
BEFORE EACH ROW IS
BEGIN
IF (/*condition for failing*/) THEN
log_error('custom error message');
RAISE_APPLICATION_ERROR(-20001, 'custom error message');
END IF;
END BEFORE EACH ROW;
END my_trigger;
/