Berkeley DB: Db::truncate
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++

### 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`

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