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61 lines
2.3 KiB
TeX
61 lines
2.3 KiB
TeX
\section{\module{dbm} ---
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Simple ``database'' interface}
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\declaremodule{builtin}{dbm}
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\platform{Unix}
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\modulesynopsis{The standard ``database'' interface, based on ndbm.}
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The \module{dbm} module provides an interface to the \UNIX{}
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(\code{n})\code{dbm} library. Dbm objects behave like mappings
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(dictionaries), except that keys and values are always strings.
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Printing a dbm object doesn't print the keys and values, and the
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\method{items()} and \method{values()} methods are not supported.
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This module can be used with the ``classic'' ndbm interface, the BSD
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DB compatibility interface, or the GNU GDBM compatibility interface.
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On \UNIX, the \program{configure} script will attempt to locate the
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appropriate header file to simplify building this module.
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The module defines the following:
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\begin{excdesc}{error}
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Raised on dbm-specific errors, such as I/O errors.
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\exception{KeyError} is raised for general mapping errors like
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specifying an incorrect key.
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\end{excdesc}
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\begin{datadesc}{library}
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Name of the \code{ndbm} implementation library used.
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\end{datadesc}
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\begin{funcdesc}{open}{filename\optional{, flag\optional{, mode}}}
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Open a dbm database and return a dbm object. The \var{filename}
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argument is the name of the database file (without the \file{.dir} or
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\file{.pag} extensions; note that the BSD DB implementation of the
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interface will append the extension \file{.db} and only create one
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file).
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The optional \var{flag} argument must be one of these values:
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\begin{tableii}{c|l}{code}{Value}{Meaning}
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\lineii{'r'}{Open existing database for reading only (default)}
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\lineii{'w'}{Open existing database for reading and writing}
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\lineii{'c'}{Open database for reading and writing, creating it if
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it doesn't exist}
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\lineii{'n'}{Always create a new, empty database, open for reading
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and writing}
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\end{tableii}
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The optional \var{mode} argument is the \UNIX{} mode of the file, used
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only when the database has to be created. It defaults to octal
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\code{0666}.
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\end{funcdesc}
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\begin{seealso}
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\seemodule{anydbm}{Generic interface to \code{dbm}-style databases.}
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\seemodule{gdbm}{Similar interface to the GNU GDBM library.}
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\seemodule{whichdb}{Utility module used to determine the type of an
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existing database.}
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\end{seealso}
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