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

# Db::del |

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    #include <db_cxx.h>

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

# Description

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.

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.

The flags value must be set to 0 or the following value:

DB_AUTO_COMMIT
  Enclose the Db::del 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.

If the specified key is not in the database, the Db::del method will return DB_NOTFOUND. Otherwise, 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.

# Errors

The Db::del method may fail and throw an exception or return a non-zero error for the following conditions:

DB_SECONDARY_BAD
  A secondary index references a nonexistent primary key.

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

EINVAL
  An invalid flag value or parameter was specified.

If the operation was selected to resolve a deadlock, the Db::del method will fail and and either return DB_LOCK_DEADLOCK or throw a DbDeadlockException exception.

The Db::del method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods. If a catastrophic error has occurred, the Db::del method may fail and either return DB_RUNRECOVERY or throw a DbRunRecoveryException, in which case all subsequent Berkeley DB calls will fail in the same way.

# Class

Db

# See Also

Databases and Related Methods`

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