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 is currently unused, and must be set to 0.
txnid
  If the operation is part of an application-specified transaction, the txnid parameter is a transaction handle returned from DbEnv::txn_begin; if the operation is part of a Berkeley DB Concurrent Data Store group, the txnid parameter is a handle returned from DbEnv::cdsgroup_begin; otherwise NULL. If no transaction handle is specified, but the operation occurs in a transactional database, the operation will be implicitly transaction protected.

### 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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