Berkeley DB: Db::put
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::put |

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###

    #include <db_cxx.h>

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

### Description: Db::put

The Db::put method stores key/data pairs in the database. The default behavior of the Db::put function is to enter the new key/data pair, replacing any previously existing key if duplicates are disallowed, or adding a duplicate data item if duplicates are allowed. If the database supports duplicates, the Db::put method adds the new data value at the end of the duplicate set. If the database supports sorted duplicates, the new data value is inserted at the correct sorted location.

Unless otherwise specified, the Db::put 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

flags
  The flags parameter must be set to 0 or one of the following values:
  DB_APPEND
    Append the key/data pair to the end of the database. For the DB_APPEND flag to be specified, the underlying database must be a Queue or Recno database. The record number allocated to the record is returned in the specified key.

    There is a minor behavioral difference between the Recno and Queue access methods for the DB_APPEND flag. If a transaction enclosing a Db::put operation with the DB_APPEND flag aborts, the record number may be decremented (and later reallocated by a subsequent DB_APPEND operation) by the Recno access method, but will not be decremented or reallocated by the Queue access method.

  DB_NODUPDATA
    In the case of the Btree and Hash access methods, enter the new key/data pair only if it does not already appear in the database.

    The DB_NODUPDATA flag may only be specified if the underlying database has been configured to support sorted duplicates. The DB_NODUPDATA flag may not be specified to the Queue or Recno access methods.

    The Db::put method will return DB_KEYEXIST if DB_NODUPDATA is set and the key/data pair already appears in the database.

  DB_NOOVERWRITE
    Enter the new key/data pair only if the key does not already appear in the database. The Db::put method call with the DB_NOOVERWRITE flag set will fail if the key already exists in the database, even if the database supports duplicates.

    The Db::put method will return DB_KEYEXIST if DB_NOOVERWRITE is set and the key already appears in the database.

data
  The data Dbt operated on.
key
  The key Dbt operated on.
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::put method may fail and throw DbException, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:

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

DB_REP_HANDLE_DEAD
  The database handle has been invalidated because a replication election unrolled a committed transaction.
DB_REP_LOCKOUT
  The operation was blocked by client/master synchronization.

EINVAL
  If a record number of 0 was specified; an attempt was made to add a record to a fixed-length database that was too large to fit; an attempt was made to do a partial put; an attempt was made to add a record to a secondary index; or if an invalid flag value or parameter was specified.

ENOSPC
  A btree exceeded the maximum btree depth (255).

If a transactional database environment operation was selected to resolve a deadlock, the Db::put 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::put 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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