CODEWITHSUNDEEP
oracle-databasetriggersoracle10g
Geo
Geo

Reputation: 3200

Triggers in Oracle and how to keep the records after a rollback

I need to create a trigger that writes changes in a shadow table. I know how to create the trigger but my challenge is that I need the records in the new table to exist even after a rollback.

This is an example of how the output will look like 

INSERT INTO department VALUES (95, 'PURCHASING', 'CHICAGO');<br>
ROLLBACK;

1 rows inserted.
rollback complete.

SELECT * FROM department_log;

DEPARTMENT_ID           DEPARTMENT_NAME       ADDRESS               OPERATION_TIME            
---------------------- -------------------- -------------------- ------------------ 
90                      HR                    CHICAGO               03-NOV-11
95                      PURCHASING            CHICAGO               03-NOV-11

SELECT * from department WHERE department_id >= 90;

DEPARTMENT_ID           DEPARTMENT_NAME       ADDRESS              
---------------------- -------------------- -------------------- 
90                      HR                    CHICAGO

Upvotes: 2

Views: 1287

Answers (2)

Justin Cave
Justin Cave

Reputation: 231741

You'll need to use autonomous transactions.

SQL> create table t (col1 number);

Table created.

SQL> create table t_shadow( col1 number, dt date );

Table created.

SQL> create trigger trg_t
  2    before insert on t
  3    for each row
  4  declare
  5    pragma autonomous_transaction;
  6  begin
  7    insert into t_shadow( col1, dt )
  8      values( :new.col1, sysdate );
  9    commit;
 10  end;
 11  /

Trigger created.

SQL> insert into t values( 1 );

1 row created.

SQL> rollback;

Rollback complete.

SQL> select * from t;

no rows selected

SQL> select * from t_shadow;

      COL1 DT
---------- ---------
         1 09-NOV-11

Note that if you find yourself using autonomous transactions for anything other than persistent logging, you are almost certainly doing something wrong. Autonomous transactions are a very dangerous and very frequently misused feature.

Upvotes: 6

Andrew
Andrew

Reputation: 27294

You would need to declare the trigger as an Autonomous Transaction 

PRAGMA AUTONOMOUS_TRANSACTION;

This decouples the trigger code from the main transaction, so even if the main insertion into the table (which fired the trigger) rollsback, the trigger is executed in a different transactional context and can commit / rollback independently.

Upvotes: 2

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