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Oracle Unrecoverable Table Option
Oracle Tips by Burleson Consulting |
Using Oracle’s UNRECOVERABLE Option
Please note that the UNRECOVERABLE
option has been deprecated and replaced with the
NOLOGGING option.
* Create index . . . unrecoverable--This is the most common
use of the unrecoverable clause, and certainly the one that makes
the most sense from an Oracle perspective. Regardless of any
transaction failures, an index can always be re-created by dropping
and redefining the index, so having an incomplete or corrupt index
would never be a problem.
* Alter table . . . add constraint . . . unrecoverable--As we
know, when a referential integrity constraint is added to a table,
the Oracle software will sometimes create an index to enforce the
constraint. Primary key, foreign key, and unique constraints may
cause Oracle to create an index, which is built in unrecoverable
mode.
* SQL*Loader--SQL*Loader is generally used when initially
populating Oracle tables from external flat files. For very large
numbers of inserts, it is best to leave the default. We already know
that in the unlikely event of an abnormal termination, the
incomplete tables must be dropped and SQL*Loader run again.
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