DBD::File(3pm)

1DBD::File(3)          User Contributed Perl Documentation         DBD::File(3)
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NAME

6       DBD::File - Base class for writing DBI drivers
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SYNOPSIS

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

15       The DBD::File module is not a true DBI driver, but an abstract base
16       class for deriving concrete DBI drivers from it. The implication is,
17       that these drivers work with plain files, for example CSV files or INI
18       files. The module is based on the SQL::Statement module, a simple SQL
19       engine.
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21       See DBI for details on DBI, SQL::Statement for details on
22       SQL::Statement and DBD::CSV or DBD::IniFile for example drivers.
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24   Metadata
25       The following attributes are handled by DBI itself and not by
26       DBD::File, thus they all work like expected:
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28           Active
29           ActiveKids
30           CachedKids
31           CompatMode             (Not used)
32           InactiveDestroy
33           Kids
34           PrintError
35           RaiseError
36           Warn                   (Not used)
37
38       The following DBI attributes are handled by DBD::File:
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40       AutoCommit
41           Always on
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43       ChopBlanks
44           Works
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46       NUM_OF_FIELDS
47           Valid after "$sth-"execute>
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49       NUM_OF_PARAMS
50           Valid after "$sth-"prepare>
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52       NAME
53           Valid after "$sth-"execute>; undef for Non-Select statements.
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55       NULLABLE
56           Not really working, always returns an array ref of one's, as
57           DBD::CSV doesn't verify input data. Valid after "$sth-"execute>;
58           undef for Non-Select statements.
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60       These attributes and methods are not supported:
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62           bind_param_inout
63           CursorName
64           LongReadLen
65           LongTruncOk
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67       Additional to the DBI attributes, you can use the following dbh
68       attribute:
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70       f_dir
71           This attribute is used for setting the directory where CSV files
72           are opened. Usually you set it in the dbh, it defaults to the
73           current directory ("."). However, it is overwritable in the
74           statement handles.
75
76       f_ext
77           This attribute is used for setting the file extension where (CSV)
78           files are opened. There are several possibilities.
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80               DBI:CSV:f_dir=data;f_ext=.csv
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82           In this case, DBD::File will open only "table.csv" if both
83           "table.csv" and "table" exist in the datadir. The table will still
84           be named "table". If your datadir has files with extensions, and
85           you do not pass this attribute, your table is named "table.csv",
86           which is probably not what you wanted. The extension is always
87           case-insensitive. The table names are not.
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89               DBI:CSV:f_dir=data;f_ext=.csv/r
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91           In this case the extension is required, and all filenames that do
92           not match are ignored.
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94       f_schema
95           This will set the schema name. Default is the owner of the folder
96           in which the table file resides.  "undef" is allowed.
97
98               my $dbh = DBI->connect ("dbi:CSV:", "", "", {
99                   f_schema => undef,
100                   f_dir    => "data",
101                   f_ext    => ".csv/r",
102                   }) or die $DBI::errstr;
103
104           The effect is that when you get table names from DBI, you can force
105           all tables into the same (or no) schema:
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107               my @tables $dbh->tables ();
108
109               # no f_schema
110               "merijn".foo
111               "merijn".bar
112
113               # f_schema => "dbi"
114               "dbi".foo
115               "dbi".bar
116
117               # f_schema => undef
118               foo
119               bar
120
121   Driver private methods
122       data_sources
123           The "data_sources" method returns a list of subdirectories of the
124           current directory in the form "DBI:CSV:f_dir=$dirname".
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126           If you want to read the subdirectories of another directory, use
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128               my ($drh) = DBI->install_driver ("CSV");
129               my (@list) = $drh->data_sources (f_dir => "/usr/local/csv_data" );
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131       list_tables
132           This method returns a list of file names inside $dbh->{f_dir}.
133           Example:
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135               my ($dbh) = DBI->connect ("DBI:CSV:f_dir=/usr/local/csv_data");
136               my (@list) = $dbh->func ("list_tables");
137
138           Note that the list includes all files contained in the directory,
139           even those that have non-valid table names, from the view of SQL.
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KNOWN BUGS

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

149       This module is currently maintained by
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151       H.Merijn Brand < h.m.brand at xs4all.nl > and Jens Rehsack  < rehsack
152       at googlemail.com >
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154       The original author is Jochen Wiedmann.
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COPYRIGHT AND LICENSE

157       Copyright (C) 2009 by H.Merijn Brand & Jens Rehsack Copyright (C) 2004
158       by Jeff Zucker Copyright (C) 1998 by Jochen Wiedmann
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160       All rights reserved.
161
162       You may freely distribute and/or modify this module under the terms of
163       either the GNU General Public License (GPL) or the Artistic License, as
164       specified in the Perl README file.
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NAME

SYNOPSIS

DESCRIPTION

KNOWN BUGS

AUTHOR

COPYRIGHT AND LICENSE

SEE ALSO