| [2] | 1 | :mod:`dbm` --- Simple "database" interface
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| 2 | ==========================================
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| 3 |
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| 4 | .. module:: dbm
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| 5 | :platform: Unix
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| 6 | :synopsis: The standard "database" interface, based on ndbm.
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| 7 |
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| 8 | .. note::
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| [391] | 9 | The :mod:`dbm` module has been renamed to :mod:`dbm.ndbm` in Python 3. The
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| [2] | 10 | :term:`2to3` tool will automatically adapt imports when converting your
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| [391] | 11 | sources to Python 3.
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| [2] | 12 |
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| 13 |
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| 14 | The :mod:`dbm` module provides an interface to the Unix "(n)dbm" library. Dbm
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| 15 | objects behave like mappings (dictionaries), except that keys and values are
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| 16 | always strings. Printing a dbm object doesn't print the keys and values, and the
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| 17 | :meth:`items` and :meth:`values` methods are not supported.
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| 18 |
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| 19 | This module can be used with the "classic" ndbm interface, the BSD DB
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| 20 | compatibility interface, or the GNU GDBM compatibility interface. On Unix, the
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| 21 | :program:`configure` script will attempt to locate the appropriate header file
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| 22 | to simplify building this module.
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| 23 |
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| 24 | The module defines the following:
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| 25 |
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| 26 |
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| 27 | .. exception:: error
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| 28 |
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| 29 | Raised on dbm-specific errors, such as I/O errors. :exc:`KeyError` is raised for
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| 30 | general mapping errors like specifying an incorrect key.
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| 31 |
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| 32 |
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| 33 | .. data:: library
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| 34 |
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| 35 | Name of the ``ndbm`` implementation library used.
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| 36 |
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| 37 |
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| 38 | .. function:: open(filename[, flag[, mode]])
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| 39 |
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| 40 | Open a dbm database and return a dbm object. The *filename* argument is the
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| 41 | name of the database file (without the :file:`.dir` or :file:`.pag` extensions;
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| 42 | note that the BSD DB implementation of the interface will append the extension
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| 43 | :file:`.db` and only create one file).
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| 44 |
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| 45 | The optional *flag* argument must be one of these values:
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| 46 |
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| 47 | +---------+-------------------------------------------+
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| 48 | | Value | Meaning |
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| 49 | +=========+===========================================+
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| 50 | | ``'r'`` | Open existing database for reading only |
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| 51 | | | (default) |
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| 52 | +---------+-------------------------------------------+
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| 53 | | ``'w'`` | Open existing database for reading and |
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| 54 | | | writing |
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| 55 | +---------+-------------------------------------------+
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| 56 | | ``'c'`` | Open database for reading and writing, |
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| 57 | | | creating it if it doesn't exist |
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| 58 | +---------+-------------------------------------------+
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| 59 | | ``'n'`` | Always create a new, empty database, open |
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| 60 | | | for reading and writing |
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| 61 | +---------+-------------------------------------------+
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| 62 |
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| 63 | The optional *mode* argument is the Unix mode of the file, used only when the
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| 64 | database has to be created. It defaults to octal ``0666`` (and will be
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| 65 | modified by the prevailing umask).
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| 66 |
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| 67 |
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| 68 | .. seealso::
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| 69 |
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| 70 | Module :mod:`anydbm`
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| 71 | Generic interface to ``dbm``\ -style databases.
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| 72 |
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| 73 | Module :mod:`gdbm`
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| 74 | Similar interface to the GNU GDBM library.
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| 75 |
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| 76 | Module :mod:`whichdb`
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| 77 | Utility module used to determine the type of an existing database.
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| 78 |
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