1 :mod:`dumbdbm` --- Portable DBM implementation

     2 ==============================================

     3 

     4 .. module:: dumbdbm

     5    :synopsis: Portable implementation of the simple DBM interface.

     6 

     7 .. note::

     8    The :mod:`dumbdbm` module has been renamed to :mod:`dbm.dumb` in Python 3.0.

     9    The :term:`2to3` tool will automatically adapt imports when converting your

    10    sources to 3.0.

    11 

    12 .. index:: single: databases

    13 

    14 .. note::

    15 

    16    The :mod:`dumbdbm` module is intended as a last resort fallback for the

    17    :mod:`anydbm` module when no more robust module is available. The :mod:`dumbdbm`

    18    module is not written for speed and is not nearly as heavily used as the other

    19    database modules.

    20 

    21 The :mod:`dumbdbm` module provides a persistent dictionary-like interface which

    22 is written entirely in Python.  Unlike other modules such as :mod:`gdbm` and

    23 :mod:`bsddb`, no external library is required.  As with other persistent

    24 mappings, the keys and values must always be strings.

    25 

    26 The module defines the following:

    27 

    28 

    29 .. exception:: error

    30 

    31    Raised on dumbdbm-specific errors, such as I/O errors.  :exc:`KeyError` is

    32    raised for general mapping errors like specifying an incorrect key.

    33 

    34 

    35 .. function:: open(filename[, flag[, mode]])

    36 

    37    Open a dumbdbm database and return a dumbdbm object.  The *filename* argument is

    38    the basename of the database file (without any specific extensions).  When a

    39    dumbdbm database is created, files with :file:`.dat` and :file:`.dir` extensions

    40    are created.

    41 

    42    The optional *flag* argument is currently ignored; the database is always opened

    43    for update, and will be created if it does not exist.

    44 

    45    The optional *mode* argument is the Unix mode of the file, used only when the

    46    database has to be created.  It defaults to octal ``0666`` (and will be modified

    47    by the prevailing umask).

    48 

    49    .. versionchanged:: 2.2

    50       The *mode* argument was ignored in earlier versions.

    51 

    52 

    53 .. seealso::

    54 

    55    Module :mod:`anydbm`

    56       Generic interface to ``dbm``\ -style databases.

    57 

    58    Module :mod:`dbm`

    59       Similar interface to the DBM/NDBM library.

    60 

    61    Module :mod:`gdbm`

    62       Similar interface to the GNU GDBM library.

    63 

    64    Module :mod:`shelve`

    65       Persistence module which stores non-string data.

    66 

    67    Module :mod:`whichdb`

    68       Utility module used to determine the type of an existing database.

    69 

    70 

    71 .. _dumbdbm-objects:

    72 

    73 Dumbdbm Objects

    74 ---------------

    75 

    76 In addition to the methods provided by the :class:`UserDict.DictMixin` class,

    77 :class:`dumbdbm` objects provide the following methods.

    78 

    79 

    80 .. method:: dumbdbm.sync()

    81 

    82    Synchronize the on-disk directory and data files.  This method is called by the

    83    :meth:`sync` method of :class:`Shelve` objects.

    84