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(python2.1-lib.info)dbm

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Simple "database" interface
===========================

The standard "database" interface, based on ndbm.

The `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 `items()' and `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 `configure' script will attempt to locate the appropriate
header file to simplify building this module.

The module defines the following:

`error'
     Raised on dbm-specific errors, such as I/O errors.  `KeyError' is
     raised for general mapping errors like specifying an incorrect key.

`library'
     Name of the `ndbm' implementation library used.

`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 `.dir' or
     `.pag' extensions; note that the BSD DB implementation of the
     interface will append the extension `.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'.

See also:
     Note: anydbm Generic interface to `dbm'-style databases.  Note:
     gdbm Similar interface to the GNU GDBM library.  Note: whichdb
     Utility module used to determine the type of an existing database.