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Berkeley DB: Db::truncate
Db::truncate
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#include <db_cxx.h>
int
Db::truncate(DbTxn *txnid, u_int32_t *countp, u_int32_t flags);
Description: Db::truncate
The Db::truncate method empties the database, discarding all records
it contains. The number of records discarded from the database is
returned in countp.
When called on a database configured with secondary indices using the
Db::associate method, the Db::truncate method truncates the primary
database and all secondary indices. A count of the records discarded
from the primary database is returned.
It is an error to call the Db::truncate method on a database with open
cursors.
The Db::truncate method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
Parameters
- countp
- The countp parameter references memory into which
the number of records discarded from the database is copied.
- flags
- The flags parameter must be set to 0 or
the following value:
- DB_AUTO_COMMIT
- Enclose the Db::truncate call within a transaction. If the call succeeds,
changes made by the operation will be recoverable. If the call fails,
the operation will have made no changes.
- txnid
- If the operation is to be transaction-protected,
(other than by specifying the DB_AUTO_COMMIT flag),
the txnid parameter is a transaction handle returned from
DbEnv::txn_begin; otherwise, NULL.
Errors
The Db::truncate method
may fail and throw
DbException,
encapsulating one of the following non-zero errors, or return one of
the following non-zero errors:
- EINVAL
- If there are open cursors in the database; or if an
invalid flag value or parameter was specified.
If a transactional database environment operation was selected to
resolve a deadlock, the Db::truncate method will fail and
either return DB_LOCK_DEADLOCK or
throw a DbDeadlockException exception.
If a Berkeley DB Concurrent Data Store database environment configured for lock timeouts was unable
to grant a lock in the allowed time, the Db::truncate method will fail and
either return DB_LOCK_NOTGRANTED or
throw a DbLockNotGrantedException exception.
Class
Db
See Also
Databases and Related Methods
Copyright (c) 1996-2004 Sleepycat Software, Inc. - All rights reserved.
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