# cpython-withatomic / Doc / libdbm.tex

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  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 \section{Built-in Module \sectcode{dbm}} \label{module-dbm} \bimodindex{dbm} The \code{dbm} module provides an interface to the \UNIX{} \code{(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 \code{items()} and \code{values()} methods are not supported. See also the \code{gdbm} module, which provides a similar interface using the GNU GDBM library. \refbimodindex{gdbm} The module defines the following constant and functions: \renewcommand{\indexsubitem}{(in module dbm)} \begin{excdesc}{error} Raised on dbm-specific errors, such as I/O errors. \code{KeyError} is raised for general mapping errors like specifying an incorrect key. \end{excdesc} \begin{funcdesc}{open}{filename\, \optional{flag\, \optional{mode}}} Open a dbm database and return a dbm object. The \var{filename} argument is the name of the database file (without the \file{.dir} or \file{.pag} extensions). The optional \var{flag} argument can be \code{'r'} (to open an existing database for reading only --- default), \code{'w'} (to open an existing database for reading and writing), \code{'c'} (which creates the database if it doesn't exist), or \code{'n'} (which always creates a new empty database). The optional \var{mode} argument is the \UNIX{} mode of the file, used only when the database has to be created. It defaults to octal \code{0666}. \end{funcdesc}