/Doc/library/dbm.rst
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- :mod:`dbm` --- Simple "database" interface
- ==========================================
- .. module:: dbm
- :platform: Unix
- :synopsis: The standard "database" interface, based on ndbm.
- .. note::
- The :mod:`dbm` module has been renamed to :mod:`dbm.ndbm` in Python 3.0. The
- :term:`2to3` tool will automatically adapt imports when converting your
- sources to 3.0.
- The :mod:`dbm` module provides an interface to the Unix "(n)dbm" library. Dbm
- objects behave like mappings (dictionaries), except that keys and values are
- always strings. Printing a dbm object doesn't print the keys and values, and the
- :meth:`items` and :meth:`values` methods are not supported.
- This module can be used with the "classic" ndbm interface, the BSD DB
- compatibility interface, or the GNU GDBM compatibility interface. On Unix, the
- :program:`configure` script will attempt to locate the appropriate header file
- to simplify building this module.
- The module defines the following:
- .. exception:: error
- Raised on dbm-specific errors, such as I/O errors. :exc:`KeyError` is raised for
- general mapping errors like specifying an incorrect key.
- .. data:: library
- Name of the ``ndbm`` implementation library used.
- .. function:: open(filename[, flag[, mode]])
- Open a dbm database and return a dbm object. The *filename* argument is the
- name of the database file (without the :file:`.dir` or :file:`.pag` extensions;
- note that the BSD DB implementation of the interface will append the extension
- :file:`.db` and only create one file).
- The optional *flag* argument must be one of these values:
- +---------+-------------------------------------------+
- | Value | Meaning |
- +=========+===========================================+
- | ``'r'`` | Open existing database for reading only |
- | | (default) |
- +---------+-------------------------------------------+
- | ``'w'`` | Open existing database for reading and |
- | | writing |
- +---------+-------------------------------------------+
- | ``'c'`` | Open database for reading and writing, |
- | | creating it if it doesn't exist |
- +---------+-------------------------------------------+
- | ``'n'`` | Always create a new, empty database, open |
- | | for reading and writing |
- +---------+-------------------------------------------+
- 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).
- .. seealso::
- Module :mod:`anydbm`
- Generic interface to ``dbm``\ -style databases.
- Module :mod:`gdbm`
- Similar interface to the GNU GDBM library.
- Module :mod:`whichdb`
- Utility module used to determine the type of an existing database.