
``dumbdbm`` --- Portable DBM implementation
*******************************************

Note: The ``dumbdbm`` module has been renamed to ``dbm.dumb`` in Python 3.
  The *2to3* tool will automatically adapt imports when converting
  your sources to Python 3.

Note: The ``dumbdbm`` module is intended as a last resort fallback for the
  ``anydbm`` module when no more robust module is available. The
  ``dumbdbm`` module is not written for speed and is not nearly as
  heavily used as the other database modules.

The ``dumbdbm`` module provides a persistent dictionary-like interface
which is written entirely in Python.  Unlike other modules such as
``gdbm`` and ``bsddb``, no external library is required.  As with
other persistent mappings, the keys and values must always be strings.

The module defines the following:

exception exception dumbdbm.error

   Raised on dumbdbm-specific errors, such as I/O errors.
   ``KeyError`` is raised for general mapping errors like specifying
   an incorrect key.

dumbdbm.open(filename[, flag[, mode]])

   Open a dumbdbm database and return a dumbdbm object.  The
   *filename* argument is the basename of the database file (without
   any specific extensions).  When a dumbdbm database is created,
   files with ``.dat`` and ``.dir`` extensions are created.

   The optional *flag* argument is currently ignored; the database is
   always opened for update, and will be created if it does not exist.

   The optional *mode* argument is the Unix mode of the file, used
   only when the database has to be created.  It defaults to octal
   ``0666`` (and will be modified by the prevailing umask).

   Changed in version 2.2: The *mode* argument was ignored in earlier
   versions.

See also:

   Module ``anydbm``
      Generic interface to ``dbm``-style databases.

   Module ``dbm``
      Similar interface to the DBM/NDBM library.

   Module ``gdbm``
      Similar interface to the GNU GDBM library.

   Module ``shelve``
      Persistence module which stores non-string data.

   Module ``whichdb``
      Utility module used to determine the type of an existing
      database.


Dumbdbm Objects
===============

In addition to the methods provided by the ``UserDict.DictMixin``
class, ``dumbdbm`` objects provide the following methods.

dumbdbm.sync()

   Synchronize the on-disk directory and data files.  This method is
   called by the ``sync()`` method of ``Shelve`` objects.
