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97 lines
3.7 KiB
TeX
97 lines
3.7 KiB
TeX
\section{\module{anydbm} ---
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Generic access to DBM-style databases}
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\declaremodule{standard}{anydbm}
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\modulesynopsis{Generic interface to DBM-style database modules.}
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\module{anydbm} is a generic interface to variants of the DBM
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database --- \refmodule{dbhash}\refstmodindex{dbhash} (requires
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\refmodule{bsddb}\refbimodindex{bsddb}),
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\refmodule{gdbm}\refbimodindex{gdbm}, or
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\refmodule{dbm}\refbimodindex{dbm}. If none of these modules is
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installed, the slow-but-simple implementation in module
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\refmodule{dumbdbm}\refstmodindex{dumbdbm} will be used.
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\begin{funcdesc}{open}{filename\optional{, flag\optional{, mode}}}
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Open the database file \var{filename} and return a corresponding object.
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If the database file already exists, the \refmodule{whichdb} module is
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used to determine its type and the appropriate module is used; if it
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does not exist, the first module listed above that can be imported is
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used.
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The optional \var{flag} argument can be
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\code{'r'} to open an existing database for reading only,
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\code{'w'} to open an existing database for reading and writing,
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\code{'c'} to create the database if it doesn't exist, or
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\code{'n'}, which will always create a new empty database. If not
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specified, the default value is \code{'r'}.
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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} (and will be modified by the prevailing umask).
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\end{funcdesc}
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\begin{excdesc}{error}
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A tuple containing the exceptions that can be raised by each of the
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supported modules, with a unique exception \exception{anydbm.error} as
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the first item --- the latter is used when \exception{anydbm.error} is
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raised.
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\end{excdesc}
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The object returned by \function{open()} supports most of the same
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functionality as dictionaries; keys and their corresponding values can
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be stored, retrieved, and deleted, and the \method{has_key()} and
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\method{keys()} methods are available. Keys and values must always be
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strings.
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\begin{seealso}
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\seemodule{dbhash}{BSD \code{db} database interface.}
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\seemodule{dbm}{Standard \UNIX{} database interface.}
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\seemodule{dumbdbm}{Portable implementation of the \code{dbm} interface.}
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\seemodule{gdbm}{GNU database interface, based on the \code{dbm} interface.}
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\seemodule{shelve}{General object persistence built on top of
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the Python \code{dbm} interface.}
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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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\section{\module{dumbdbm} ---
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Portable DBM implementation}
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\declaremodule{standard}{dumbdbm}
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\modulesynopsis{Portable implementation of the simple DBM interface.}
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A simple and slow database implemented entirely in Python. This
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should only be used when no other DBM-style database is available.
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\begin{funcdesc}{open}{filename\optional{, flag\optional{, mode}}}
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Open the database file \var{filename} and return a corresponding
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object. The \var{flag} argument, used to control how the database is
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opened in the other DBM implementations, is ignored in
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\module{dumbdbm}; the database is always opened for update, and will
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be created if it does not exist.
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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} (and will be modified by the prevailing umask).
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\versionchanged[The \var{mode} argument was ignored in earlier
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versions]{2.2}
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\end{funcdesc}
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\begin{excdesc}{error}
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Raised for errors not reported as \exception{KeyError} errors.
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\end{excdesc}
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\begin{seealso}
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\seemodule{anydbm}{Generic interface to \code{dbm}-style databases.}
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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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