NAME

QDBM_File - Tied access to Quick Database Manager

SYNOPSIS

use QDBM_File;

# hash db

[$db =] tie %hash, 'QDBM_File', $filename, [$flags, $mode, $buckets];
[$db =] tie %hash, 'QDBM_File::Multiple', $filename, [$flags, $mode, $buckets, $directories];
[$db =] tie %hash, 'QDBM_File::Multiple::LOB', $filename, [$flags, $mode, $buckets, $directories];

# b+tree
# $compare_sub example: sub { $_[0] cmp $_[1] }

[$db =] tie %hash, 'QDBM_File::BTree', $filename, [$flags, $mode, $compare_sub];
[$db =] tie %hash, 'QDBM_File::BTree::Multiple', $filename, [$flags, $mode, $compare_sub];

# inverted index

$db = QDBM_File::InvertedIndex->new($filename, [$flags]);

# hash db, btree, inverted index common api

$int  = $db->get_size();
$name = $db->get_name();
$int  = $db->get_mtime();
$bool = $db->sync();
$bool = $db->optimize([$buckets]);
$bool = $db->iterator_init();
$bool = $db->is_writable();
$bool = $db->is_fatal_error();
$msg  = $db->get_error();

# hash db, btree common api
$bool = $db->STORE($key, $value, [$overlap_flags]);
$int  = $db->get_record_size($key);
$int  = $db->count_records();
$bool = $class->repair($filename);
$bool = $db->export_db($filename);
$bool = $db->import_db($filename);

# hash db only
$value = $db->FETCH($key, [$start, $offset]);
$bool  = $db->set_align($align);
$bool  = $db->set_fbp_size($size);
$int   = $db->count_buckets();
$int   = $db->count_used_buckets();

# Large Object: QDBM_File::Multiple only
$bool  = $db->store_lob($key, $value, [$overlap_flags]);
$value = $db->fetch_lob($key);
$bool  = $db->delete_lob($key);
$bool  = $db->exists_lob($key);
$int   = $db->count_lob_records();

# btree only
$bool   = $db->store_list($key, @values);
@values = $db->fetch_list($key);
$bool   = $db->delete_list($key);

$int    = $db->count_match_records($key);
$int    = $db->count_leafs();
$int    = $db->count_non_leafs();

$bool   = $db->move_first();
$bool   = $db->move_last();
$bool   = $db->move_next();
$bool   = $db->move_prev();
$bool   = $db->move_forward($key);
$bool   = $db->move_backword($key);

$key    = $db->get_current_key();
$value  = $db->get_current_value();
$bool   = $db->store_current($value);
$bool   = $db->store_after($value);
$bool   = $db->store_before($value);
$bool   = $db->delete_current($value);

$bool   = $db->begin_transaction();
$bool   = $db->commit();
$bool   = $db->rollback();

$db->set_tuning(
    $max_leaf_record,
    $max_non_leaf_index,
    $max_cache_leaf,
    $max_cache_non_leaf
);

# DBM_Filter
$old_filter = $db->filter_store_key  ( sub { ... } );
$old_filter = $db->filter_store_value( sub { ... } );
$old_filter = $db->filter_fetch_key  ( sub { ... } );
$old_filter = $db->filter_fetch_value( sub { ... } );

untie %hash;

# inverted index api
$doc  = $class->create_document($uri);
$bool = $db->store_document($doc, [$max_words, $is_overwrite]);

$doc  = $db->get_document_by_uri($uri);
$doc  = $db->get_document_by_id($id);
$id   = $db->get_document_id($uri);
$bool = $db->delete_document_by_uri($uri);
$bool = $db->delete_document_by_id($id);
$bool = $db->exists_document_by_uri($uri);
$bool = $db->exists_document_by_id($id);

$doc   = $db->get_next_document();
@id    = $db->search_document($word);
$int   = $db->search_document_count($word);
$bool  = $class->merge($filename, @filenames);
%score = $db->get_scores($doc, $max);

$db->set_tuning(
    $index_buckets,
    $inverted_index_division_num,
    $dirty_buffer_buckets,
    $dirty_buffer_size
);

$db->set_char_class($space, $delimiter, $glue);
@appearance_words = $db->analyze_text($text);
@appearance_words = $class->analyze_text($text);
$normalized_word  = $class->normalize_word($word);
@id = $db->query($query);

# document api
$doc = QDBM_File::InvertedIndex::Document->new($uri);
$doc->set_attribute($name, $value);
$value = $doc->get_attribute($name);
$doc->add_word($normalized_word, $appearance_word);
$uri = $doc->get_uri();
$id  = $doc->get_id();
@normalized_words = $doc->get_normalized_words();
@appearance_words = $doc->get_appearance_words();
%score = $doc->get_scores($max, [$db]);

DESCRIPTION

QDBM_File is a module which allows Perl programs to make use of the facilities provided by the qdbm library. If you use this module, you should read QDBM manual pages.

Quick Database Manager is a high performance dbm library maintained by Mikio Hirabayashi. QDBM_File provides various API, Depot, Curia, Villa, Vista and Odeum. Documents are available at http://qdbm.sourceforge.net/

EXPORT

QDBM_File exports these overlap flags:

QD_OVER

Means the specified value overwrites the existing one.

QD_KEEP

Means the existing value is kept.

QD_CAT

Means the specified value is concatenated at the end of the existing value.

QD_DUP

Means duplication of keys is allowed and the specified value is added as the last one. It is BTree interface only.

QD_DUPR

Means duplication of keys is allowed and the specified value is added as the first one. It is BTree interface only.

METHODS

TIEHASH

TIEHASH interface is similar to other xDBM_File.

use Fcntl;
use QDBM_File;

my %hash;
my $filename = "filename";
my $db = tie %hash, "QDBM_File", $filename, O_RDWR|O_CREAT, 0644;
$hash{"key"} = "value";

Hash db has optional argument $buckets, specifies bucket number of db, and Q::Multiple has $directories, specifies division number of directory.

Q::BTree has $compare_sub, used for key comparison. It must return -1 or 0 or 1. If $compare_sub is omitted, dictionary order is used.

sub { $_[0] cmp $_[1] } # ordered by dictionary
sub { $_[0] <=> $_[1] } # ordered by number

STORE

If using STORE as method, $overlap_flags can be used. If omitted, QD_OVER is used.

$db->STORE("key", "value", QD_CAT);

AUTHOR

Toshiyuki Yamato, <toshiyuki.yamato@gmail.com>

BUGS AND WARNINGS

Currently umask flags is ignored implicitly, 0644 is always used. It is used for other xDBM_File compatibility.

QDBM_File::Multiple::LOB is tied interface wrapper of store_lob, fetch_lob, exists_lob, delete_lob. When using LOB, empty key can not be used, and traversal access (keys, values, each) is not available. It is a little inconvenient, so I recommend using QDBM_File::Multiple and xxxxx_lob api directly.

SEE ALSO

DB_File(3), perldbmfilter.

COPYRIGHT & LICENSE

Copyright 2007 Toshiyuki Yamato, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.