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author | Georg Brandl <georg@python.org> | 2008-05-26 10:29:35 (GMT) |
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committer | Georg Brandl <georg@python.org> | 2008-05-26 10:29:35 (GMT) |
commit | 0a7ac7d70d370544c6a9d118bbbd6886ad4f5ce5 (patch) | |
tree | ec61fd6d53e6425b8639567860140c724ea7bc63 /Doc/library/gdbm.rst | |
parent | e6f00637be87c8f5f0e50bf317d684ea421a6d19 (diff) | |
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Create the dbm package from PEP 3108. #2881.
Diffstat (limited to 'Doc/library/gdbm.rst')
-rw-r--r-- | Doc/library/gdbm.rst | 122 |
1 files changed, 0 insertions, 122 deletions
diff --git a/Doc/library/gdbm.rst b/Doc/library/gdbm.rst deleted file mode 100644 index f69e667..0000000 --- a/Doc/library/gdbm.rst +++ /dev/null @@ -1,122 +0,0 @@ - -:mod:`gdbm` --- GNU's reinterpretation of dbm -============================================= - -.. module:: gdbm - :platform: Unix - :synopsis: GNU's reinterpretation of dbm. - - -.. index:: module: dbm - -This module is quite similar to the :mod:`dbm` module, but uses ``gdbm`` instead -to provide some additional functionality. Please note that the file formats -created by ``gdbm`` and ``dbm`` are incompatible. - -The :mod:`gdbm` module provides an interface to the GNU DBM library. ``gdbm`` -objects behave like mappings (dictionaries), except that keys and values are -always strings. Printing a ``gdbm`` object doesn't print the keys and values, -and the :meth:`items` and :meth:`values` methods are not supported. - -The module defines the following constant and functions: - - -.. exception:: error - - Raised on ``gdbm``\ -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 ``gdbm`` database and return a ``gdbm`` object. The *filename* argument - is the name of the database file. - - The optional *flag* argument can be: - - +---------+-------------------------------------------+ - | 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 following additional characters may be appended to the flag to control - how the database is opened: - - +---------+--------------------------------------------+ - | Value | Meaning | - +=========+============================================+ - | ``'f'`` | Open the database in fast mode. Writes | - | | to the database will not be synchronized. | - +---------+--------------------------------------------+ - | ``'s'`` | Synchronized mode. This will cause changes | - | | to the database to be immediately written | - | | to the file. | - +---------+--------------------------------------------+ - | ``'u'`` | Do not lock database. | - +---------+--------------------------------------------+ - - Not all flags are valid for all versions of ``gdbm``. The module constant - :const:`open_flags` is a string of supported flag characters. The exception - :exc:`error` is raised if an invalid flag is specified. - - 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``. - -In addition to the dictionary-like methods, ``gdbm`` objects have the following -methods: - - -.. function:: firstkey() - - It's possible to loop over every key in the database using this method and the - :meth:`nextkey` method. The traversal is ordered by ``gdbm``'s internal hash - values, and won't be sorted by the key values. This method returns the starting - key. - - -.. function:: nextkey(key) - - Returns the key that follows *key* in the traversal. The following code prints - every key in the database ``db``, without having to create a list in memory that - contains them all:: - - k = db.firstkey() - while k != None: - print(k) - k = db.nextkey(k) - - -.. function:: reorganize() - - If you have carried out a lot of deletions and would like to shrink the space - used by the ``gdbm`` file, this routine will reorganize the database. ``gdbm`` - will not shorten the length of a database file except by using this - reorganization; otherwise, deleted file space will be kept and reused as new - (key, value) pairs are added. - - -.. function:: sync() - - When the database has been opened in fast mode, this method forces any - unwritten data to be written to the disk. - - -.. seealso:: - - Module :mod:`anydbm` - Generic interface to ``dbm``\ -style databases. - - Module :mod:`whichdb` - Utility module used to determine the type of an existing database. - |