DDL Recovery
The Oracle DBMS does not support recovery of DDL statements. That is, CREATE and DROP statements cannot be rolled back. Because Ingres supports DDL recovery, its recovery behavior differs from the Oracle gateway's behavior.
Example:
drop table testtable;
create table testtable (col1 varchar (20));
insert into testtable (col1) values ('original table');
commit;
drop table testtable;
rollback;
select * from testtable;
Results:
• Oracle-“table not found” message displayed because the “rollback” DDL statement is not rolled back.
• Ingres and all other gateways -testtable exists and the row containing the value “original table” will be retrieved.
The failure of the Oracle gateway to perform recovery of DDL statements must be taken into account when designing portable atomic transactions.