This causes all the rows in the table to be deleted. Log records are written. If the table is large(in terms of millions of records), a very large active log space is required. DELETE Triggers are fired.
2. Using IMPORT/LOAD
IMPORT from /dev/null of del replace into <tablename> LOAD from /dev/null of del replace into <tablename> NONRECOVERABLE
More privelages are required for these tasks. IMPORT .. REPLACE requires CONTROL on the table and LOAD requires LOAD Authority on the table. Good thing about this is that there is minimal logging. The tables may be left in check pending state. DELETE Triggers are not fired.
From the database recovery point of view, it is advisable to use IMPORT
3. Using NLI
ALTER TABLE <tablename> NOT LOGGED INITIALLY WITH EMPLY TABLE
The table should have been created with the NLI Option. No logging is done. DELETE triggers are not fired.