Edit File: dumbdbm.txt
:mod:`dumbdbm` --- Portable DBM implementation ============================================== .. module:: dumbdbm :synopsis: Portable implementation of the simple DBM interface. .. note:: The :mod:`dumbdbm` module has been renamed to :mod:`dbm.dumb` in Python 3. The :term:`2to3` tool will automatically adapt imports when converting your sources to Python 3. .. index:: single: databases .. note:: The :mod:`dumbdbm` module is intended as a last resort fallback for the :mod:`anydbm` module when no more robust module is available. The :mod:`dumbdbm` module is not written for speed and is not nearly as heavily used as the other database modules. The :mod:`dumbdbm` module provides a persistent dictionary-like interface which is written entirely in Python. Unlike other modules such as :mod:`gdbm` and :mod:`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:: error Raised on dumbdbm-specific errors, such as I/O errors. :exc:`KeyError` is raised for general mapping errors like specifying an incorrect key. .. function:: 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 :file:`.dat` and :file:`.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). .. versionchanged:: 2.2 The *mode* argument was ignored in earlier versions. .. seealso:: Module :mod:`anydbm` Generic interface to ``dbm``\ -style databases. Module :mod:`dbm` Similar interface to the DBM/NDBM library. Module :mod:`gdbm` Similar interface to the GNU GDBM library. Module :mod:`shelve` Persistence module which stores non-string data. Module :mod:`whichdb` Utility module used to determine the type of an existing database. .. _dumbdbm-objects: Dumbdbm Objects --------------- In addition to the methods provided by the :class:`UserDict.DictMixin` class, :class:`dumbdbm` objects provide the following methods. .. method:: dumbdbm.sync() Synchronize the on-disk directory and data files. This method is called by the :meth:`sync` method of :class:`Shelve` objects.