#include <db_cxx.h>

int
Db::del(DbTxn *txnid, Dbt *key, u_int32_t flags);

The Db::del method removes key/data pairs from the database. The key/data pair associated with the specified key is discarded from the database. In the presence of duplicate key values, all records associated with the designated key will be discarded.

When called on a database that has been made into a secondary index using the Db::associate method, the Db::del method deletes the key/data pair from the primary database and all secondary indices.

The Db::del method will return DB_NOTFOUND if the specified key is not in the database. The Db::del method will return DB_KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted. Unless otherwise specified, the Db::del 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.

• The flags parameter is currently unused, and must be set to 0.

• The key Dbt operated on.

• 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.

The Db::del method may fail and throw DbException, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:

• The database handle has been invalidated because a replication election unrolled a committed transaction.

• The operation was blocked by client/master synchronization.

• A secondary index references a nonexistent primary key.

• An attempt was made to modify a read-only database.

• An invalid flag value or parameter was specified.

If a transactional database environment operation was selected to resolve a deadlock, the Db::del 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::del method will fail and either return DB_LOCK_NOTGRANTED or throw a DbLockNotGrantedException exception.