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93 lines
2.8 KiB
93 lines
2.8 KiB
:mod:`dumbdbm` --- Portable DBM implementation
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==============================================
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.. module:: dumbdbm
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:synopsis: Portable implementation of the simple DBM interface.
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.. note::
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The :mod:`dumbdbm` module has been renamed to :mod:`dbm.dumb` in Python 3.
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The :term:`2to3` tool will automatically adapt imports when converting your
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sources to Python 3.
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.. index:: single: databases
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.. note::
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The :mod:`dumbdbm` module is intended as a last resort fallback for the
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:mod:`anydbm` module when no more robust module is available. The :mod:`dumbdbm`
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module is not written for speed and is not nearly as heavily used as the other
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database modules.
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The :mod:`dumbdbm` module provides a persistent dictionary-like interface which
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is written entirely in Python. Unlike other modules such as :mod:`gdbm` and
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:mod:`bsddb`, no external library is required. As with other persistent
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mappings, the keys and values must always be strings.
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The module defines the following:
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.. exception:: error
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Raised on dumbdbm-specific errors, such as I/O errors. :exc:`KeyError` is
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raised for general mapping errors like specifying an incorrect key.
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.. function:: open(filename[, flag[, mode]])
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Open a dumbdbm database and return a dumbdbm object. The *filename* argument is
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the basename of the database file (without any specific extensions). When a
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dumbdbm database is created, files with :file:`.dat` and :file:`.dir` extensions
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are created.
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The optional *flag* argument is currently ignored; the database is always opened
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for update, and will be created if it does not exist.
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The optional *mode* argument is the Unix mode of the file, used only when the
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database has to be created. It defaults to octal ``0666`` (and will be modified
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by the prevailing umask).
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.. versionchanged:: 2.2
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The *mode* argument was ignored in earlier versions.
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In addition to the dictionary-like methods, ``dumbdm`` objects
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provide the following method:
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.. function:: close()
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Close the ``dumbdm`` database.
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.. seealso::
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Module :mod:`anydbm`
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Generic interface to ``dbm``\ -style databases.
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Module :mod:`dbm`
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Similar interface to the DBM/NDBM library.
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Module :mod:`gdbm`
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Similar interface to the GNU GDBM library.
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Module :mod:`shelve`
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Persistence module which stores non-string data.
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Module :mod:`whichdb`
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Utility module used to determine the type of an existing database.
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.. _dumbdbm-objects:
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Dumbdbm Objects
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---------------
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In addition to the methods provided by the :class:`UserDict.DictMixin` class,
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:class:`~dumbdbm.dumbdbm` objects provide the following methods.
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.. method:: dumbdbm.sync()
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Synchronize the on-disk directory and data files. This method is called by the
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:meth:`sync` method of :class:`Shelve` objects.
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