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DBD::File(3)          User Contributed Perl Documentation         DBD::File(3)



NAME
       DBD::File - Base class for writing DBI drivers

SYNOPSIS
        This module is a base class for writing other DBDs.
        It is not intended to function as a DBD itself.
        If you want to access flatfiles, use DBD::AnyData, or DBD::CSV,
        (both of which are subclasses of DBD::File).

DESCRIPTION
       The DBD::File module is not a true DBI driver, but an abstract base class for deriving concrete DBI drivers
       from it. The implication is, that these drivers work with plain files, for example CSV files or INI files. The
       module is based on the SQL::Statement module, a simple SQL engine.

       See DBI for details on DBI, SQL::Statement for details on SQL::Statement and DBD::CSV or DBD::IniFile for exam-
       ple drivers.

       Metadata

       The following attributes are handled by DBI itself and not by DBD::File, thus they all work like expected:

           Active
           ActiveKids
           CachedKids
           CompatMode             (Not used)
           InactiveDestroy
           Kids
           PrintError
           RaiseError
           Warn                   (Not used)

       The following DBI attributes are handled by DBD::File:

       AutoCommit
           Always on

       ChopBlanks
           Works

       NUM_OF_FIELDS
           Valid after "$sth-"execute>

       NUM_OF_PARAMS
           Valid after "$sth-"prepare>

       NAME
           Valid after "$sth-"execute>; undef for Non-Select statements.

       NULLABLE
           Not really working, always returns an array ref of one's, as DBD::CSV doesn't verify input data. Valid
           after "$sth-"execute>; undef for Non-Select statements.

       These attributes and methods are not supported:

           bind_param_inout
           CursorName
           LongReadLen
           LongTruncOk

       Additional to the DBI attributes, you can use the following dbh attribute:

       f_dir
           This attribute is used for setting the directory where CSV files are opened. Usually you set it in the dbh,
           it defaults to the current directory ("."). However, it is overwritable in the statement handles.

       Driver private methods


       data_sources
           The "data_sources" method returns a list of subdirectories of the current directory in the form
           "DBI:CSV:f_dir=$dirname".

           If you want to read the subdirectories of another directory, use

               my($drh) = DBI->install_driver("CSV");
               my(@list) = $drh->data_sources('f_dir' => '/usr/local/csv_data' );

       list_tables
           This method returns a list of file names inside $dbh->{'f_dir'}.  Example:

               my($dbh) = DBI->connect("DBI:CSV:f_dir=/usr/local/csv_data");
               my(@list) = $dbh->func('list_tables');

           Note that the list includes all files contained in the directory, even those that have non-valid table
           names, from the view of SQL.

KNOWN BUGS
       ?       The module is using flock() internally. However, this function is not available on all platforms. Using
               flock() is disabled on MacOS and Windows 95: There's no locking at all (perhaps not so important on
               MacOS and Windows 95, as there's a single user anyways).

AUTHOR AND COPYRIGHT
       This module is currently maintained by

       Jeff Zucker < jzucker @ cpan.org >

       The original author is Jochen Wiedmann.

       Copyright (C) 2004 by Jeff Zucker Copyright (C) 1998 by Jochen Wiedmann

       All rights reserved.

       You may freely distribute and/or modify this module under the terms of either the GNU General Public License
       (GPL) or the Artistic License, as specified in the Perl README file.

SEE ALSO
       DBI, Text::CSV_XS, SQL::Statement



perl v5.8.8                       2007-10-10                      DBD::File(3)