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# -*- Mode: cperl -*- |
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# $Basename: Database.pm $ |
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# $Revision: 1.14 $ |
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# Author : Ulrich Pfeifer |
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# Created On : Thu Aug 8 09:44:13 1996 |
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# Last Modified By: Ulrich Pfeifer |
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# Last Modified On: Sat Apr 15 16:15:29 2000 |
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# Language : CPerl |
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# |
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# (C) Copyright 1996-2000, Ulrich Pfeifer |
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# |
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|
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=head1 NAME |
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|
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WAIT::Database - Module fo maintaining WAIT databases |
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|
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=head1 SYNOPSIS |
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|
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require WAIT::Database; |
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|
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=head1 DESCRIPTION |
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|
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The modules handles creating, opening, and deleting of databases and |
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tables. |
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|
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=cut |
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|
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package WAIT::Database; |
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|
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use strict; |
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use FileHandle (); |
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use File::Path qw(rmtree); |
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use WAIT::Table (); |
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use BerkeleyDB; |
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use Fcntl; |
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use Carp; # will use autouse later |
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use Storable qw(nfreeze thaw); |
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use vars qw($VERSION); |
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use Data::Dumper; |
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|
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$VERSION = "2.000"; |
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|
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#$WAIT::Database::Pagesize = 1*1024; |
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#$WAIT::Database::Cachesize = 4*1024*1024; |
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|
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# use autouse Carp => qw( croak($) ); |
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|
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=head2 Constructor create |
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|
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$db = WAIT::Database->create( |
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directory => '/dir/to/database/' |
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name => 'name', |
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); |
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|
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Create a new database. |
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|
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=over 10 |
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|
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=item B<name> I<name> |
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|
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Mandatory name of database |
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|
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=item B<directory> I<directory> |
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|
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Directory which should contain the database (defaults to the current |
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directory). |
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|
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=item B<uniqueatt> I<true> |
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|
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If given, the database will require unique attributes over all tables. |
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|
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The method will croak on failure. |
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|
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=back |
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|
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=cut |
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|
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sub create { |
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my $type = shift; |
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my %parm = @_; |
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my $self = {}; |
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bless $self => ref($type) || $type; |
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my $dir = $parm{directory} || '.'; |
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my $name = $parm{name}; |
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|
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croak("No name specified") unless ($name); |
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|
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croak("Directory '$dir' does not exits: $!") unless (-d $dir); |
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|
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if (-d "$dir/$name") { |
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carp "Warning: directory '$dir/$name' already exists\n"; |
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} else { |
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unless (mkdir "$dir/$name", 0775) { |
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croak("Could not mkdir '$dir/$name': $!"); |
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} |
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} |
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|
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$self->{dir} = $dir; |
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$self->{name} = $name; |
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|
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my $env = BerkeleyDB::Env->new( |
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-Home => $self->path, |
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-Flags => DB_CREATE|DB_INIT_MPOOL|DB_INIT_CDB|DB_PRIVATE, |
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# Cachesize => 1024*1024*8, |
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# Pagesize => 8*1024, # environment doesn't understand Pagesize parameter! |
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-Verbose => 1, |
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-ErrFile => $self->path."/error.log", |
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); |
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unless ($env) { |
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confess("Could not create environment: $BerkeleyDB::Error"); |
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} |
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|
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$self->{env} = $env; |
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|
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# apperently (! learned from trial and error) while the Env doesn't |
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# understand Pagesize, the very first table needs to set it up if we |
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# want to deviate from the default. And all tables need to follow |
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# this lead. I'm doing so explicitly, it looks prettier to me |
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$self->{_attr} = BerkeleyDB::Btree->new( |
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-Filename => $self->maindbfile, |
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-Subname => "_attr", |
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-Flags => DB_CREATE, |
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-Mode => 0664, |
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-Env => $env, |
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$WAIT::Database::Cachesize?(Cachesize => $WAIT::Database::Cachesize):(), |
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$WAIT::Database::Pagesize?(Pagesize => $WAIT::Database::Pagesize):(), |
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); |
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|
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unless (defined($self->{_attr})) { |
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die("Cannot open [".$self->maindbfile."] _attr: $BerkeleyDB::Error"); |
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} |
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|
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|
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# Use of BerkeleyDB::Env->new here could maybe some day be a way to |
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# introduce a smart locking mechanism? Whatever... it is currently |
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# kein Thema: remember, that the database has a $self->path which |
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# is a *directory* and there are no berkeley tables in this |
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# directory, but there is one subdirectory in this directory for |
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# *each* *table* object. |
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|
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$self->{uniqueatt} = $parm{uniqueatt}; |
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$self->{mode} = O_RDWR; |
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$self; |
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} |
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|
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|
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=head2 Constructor open |
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|
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$db = WAIT::Database->open( |
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name => "foo", |
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directory => "bar" |
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); |
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|
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Open an existing database I<foo> in directory I<bar>. |
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|
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=cut |
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|
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sub open { |
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my $type = shift; |
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my %parm = @_; |
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my $dir = $parm{directory} || '.'; |
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my $name = $parm{name} or croak "No name specified"; |
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my $self = bless {}, ref($type) || $type; |
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|
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croak("Directory '$dir' does not exits: $!") unless (-d $dir); |
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if (!-d "$dir/$name") { |
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carp "Warning: database '$dir/$name' doesn't exist\n"; |
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return; |
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} |
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my $mode = (exists $parm{mode})?$parm{mode}:(O_CREAT | O_RDWR); |
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$self->{dir} = $dir; # will be overwritten by the thaw below, but we need it now |
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$self->{name} = $name; |
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|
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my $env; |
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|
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return if (! -d $self->path); |
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|
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my $flags = DB_CREATE|DB_INIT_MPOOL|DB_INIT_CDB; |
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|
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$env = BerkeleyDB::Env->new( |
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-Home => $self->path, |
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-Flags => $flags, |
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); |
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unless ($env) { |
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return if ($parm{mode} & O_RDWR); |
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confess("Could not create environment in [".$self->path."]: $BerkeleyDB::Error"); |
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} |
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|
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#warn "DEBUG: trying to open the database for _attr"; |
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my $maindbfile = $self->maindbfile; |
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my $attr = BerkeleyDB::Btree->new( |
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-Filename => $maindbfile, |
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-Subname => "_attr", |
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$env ? (-Env => $env) : (-Flags => DB_RDONLY), |
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); |
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unless (defined($attr)) { |
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return if ($parm{mode} & O_RDWR); |
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croak "Cannot open [$maindbfile] _attr: $BerkeleyDB::Error; mdbf[$maindbfile] env[$env]"; |
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} |
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|
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#warn "DEBUG: opened the database for _attr"; |
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$attr->db_get(0, my $dat); |
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#warn sprintf "DEBUG: got _attr record. time[%.6f] length(dat)[%d]", Time::HiRes::time(), length $dat; |
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$self = thaw $dat; |
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#warn sprintf "DEBUG: thawed _attr rec. time[%.6f]", Time::HiRes::time(); |
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$self->{_attr} = $attr; |
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|
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return unless defined $self; |
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|
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$self->{mode} = $mode; |
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$self->{env} = $env; |
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$self->{dir} = $dir; # yes, again |
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$self->{name} = $name; |
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$self->walkncomplete; |
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|
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$self; |
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} |
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|
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sub walkncomplete { |
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my $self = shift; |
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$self->maindbfile; |
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$self->path; |
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for my $t (values %{$self->{tables} || {}}) { |
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$t->{path} ||= $self->{path}; |
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$t->{maindbfile} ||= $self->{maindbfile}; |
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$t->{mode} = $self->{mode}; |
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for my $ind (values %{$t->{indexes}}) { |
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$ind->{path} ||= $self->{path}; |
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$ind->{maindbfile} ||= $self->{maindbfile}; |
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$ind->{mode} = $self->{mode}; |
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} |
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for my $inv (values %{$t->{inverted}}) { |
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for my $ind (@$inv) { |
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$ind->{path} ||= $self->{path}; |
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$ind->{maindbfile} ||= $self->{maindbfile}; |
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$ind->{mode} = $self->{mode}; |
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} |
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} |
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} |
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} |
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|
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|
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=head2 close |
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|
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Close a database saving all meta data after closing all associated tables. |
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|
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$db->close; |
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|
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=cut |
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|
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sub close { |
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# my $self = shift would increase refcount! |
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my $self = $_[0]; |
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|
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for my $table (values %{$self->{tables}}) { |
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$table->close if ref($table); |
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} |
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return 1 unless $self->{mode} & (O_RDWR | O_CREAT); |
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|
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my $env = $self->{env}; |
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|
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for my $att (qw(path maindbfile name env)) { |
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delete $self->{$att} || confess "can't delete '$att'"; |
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} |
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|
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my $db = $self->{_attr}; |
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delete $self->{_attr} || confess "can't delete _attr"; |
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|
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my $dat = nfreeze $self; |
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$db->db_put(0, $dat); |
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|
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undef $db; |
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|
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#warn "DEBUG: Removing env[$env] before closing database"; |
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undef $env; |
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#warn "DEBUG: Removed it."; |
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|
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undef $_[0]; |
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return 1; |
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} |
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|
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|
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=head2 dispose |
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|
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Dispose a database. Remove all associated files. This may fail if the |
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database or one of its tables is still open. Failure will be indicated |
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by a false return value. |
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|
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$db->dispose; |
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|
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WAIT::Database->dispose(name=>'name', directory=>'/dir/to/db/'); |
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|
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=cut |
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|
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sub dispose { |
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# my $self = shift would increase refcount! |
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|
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my $path; |
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|
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if (ref $_[0]) { # called with instance |
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croak "no mode" unless defined($_[0]->{mode}); |
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croak "Database readonly" unless $_[0]->{mode} & (O_CREAT | O_RDWR); |
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$path = $_[0]->path; |
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$_[0]->close; |
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} else { |
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shift; |
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my %parm = @_; |
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my $base = $parm{directory} || '.'; |
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my $name = $parm{name} || croak "No name specified"; |
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$path = "$base/$name"; |
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} |
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croak "No such database '$path'" unless -e "$path"; |
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|
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#warn "DEBUG: removing $path"; |
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my $ret = rmtree($path, 0, 1); |
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|
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return $ret; |
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} |
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|
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|
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=head2 C<$db-E<gt>create_table(name =E<gt>> I<tname>, ... C<);> |
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|
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Create a new table with name I<tname>. All parameters are passed to |
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C<WAIT::Table-E<gt>new> together with a filename to use. See |
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L<WAIT::Table> for which attributes are required. The method returns a |
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table handle (C<WAIT::Table::Handle>). |
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|
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=cut |
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|
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sub create_table { |
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my $self = shift; |
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my %parm = @_; |
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my $name = $parm{name} or croak "create_table: No name specified"; |
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my $attr = $parm{attr} or croak "create_table: No attributes specified"; |
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my $path = $self->path; |
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|
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croak "Database readonly" unless $self->{mode} & (O_CREAT | O_RDWR); |
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|
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if (defined $self->{tables}->{$name}) { |
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die "Table '$name' already exists"; |
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} |
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|
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if ($self->{uniqueatt}) { |
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for (@$attr) { # attribute names must be uniqe |
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if ($self->{attr}->{$_}) { |
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croak("Attribute '$_' is not unique") |
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} |
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} |
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} |
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$self->{tables}->{$name} = WAIT::Table->new(path => "$path/$name", |
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database => $self, |
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env => $self->{env}, |
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maindbfile => $self->maindbfile, |
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tablename => $name, |
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%parm); |
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unless (defined $self->{tables}->{$name}) {# fail gracefully |
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delete $self->{tables}->{$name}; |
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return undef; |
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} |
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|
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if ($self->{uniqueatt}) { |
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# remember table name for each attribute |
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map ($self->{attr}->{$_} = $name, @$attr); |
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} |
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WAIT::Table::Handle->new($self, $name); |
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} |
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|
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=head2 maindbfile |
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|
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Name of BerekelyDB database (without path) |
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|
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my $bdb = $db->maindbfile; |
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|
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=cut |
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|
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sub maindbfile { |
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my($self,$path) = @_; |
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return $self->{maindbfile} if $self->{maindbfile}; |
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$path ||= $self->path; |
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confess "no path argument or attribute" unless $path; |
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$self->{maindbfile} = "etat"; |
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} |
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|
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=head2 path |
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|
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Path to database |
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|
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my $db_path = $db->path; |
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|
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=cut |
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|
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sub path { |
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my $self = shift; |
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return $self->{path} if $self->{path}; |
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confess("no attribut dir?") unless $self->{dir}; |
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confess("no attribut name?") unless $self->{name}; |
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$self->{path} = "$self->{dir}/$self->{name}"; |
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} |
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|
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=head2 C<$db-E<gt>table(name =E<gt>> I<tname>C<);> |
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|
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Open a new table with name I<tname>. The method |
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returns a table handle (C<WAIT::Table::Handle>). |
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|
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=cut |
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|
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sub sync { |
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my $self = shift; |
| 409 |
|
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for (values %{$self->{tables}}) { |
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$_->sync; |
| 412 |
} |
| 413 |
} |
| 414 |
|
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sub table { |
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my $self = shift; |
| 417 |
my %parm = @_; |
| 418 |
my $name = $parm{name} or croak "No name specified"; |
| 419 |
|
| 420 |
if (defined $self->{tables}->{$name}) { |
| 421 |
if (exists $parm{mode}) { |
| 422 |
$self->{tables}->{$name}->{mode} = $parm{mode}; |
| 423 |
} else { |
| 424 |
$self->{tables}->{$name}->{mode} = $self->{mode}; |
| 425 |
} |
| 426 |
WAIT::Table::Handle->new($self,$name); |
| 427 |
} else { |
| 428 |
croak "No such table '$name'"; |
| 429 |
} |
| 430 |
} |
| 431 |
|
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|
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=head2 drop |
| 434 |
|
| 435 |
Drop the table named I<tname>. The table should be closed before |
| 436 |
calling B<drop>. |
| 437 |
|
| 438 |
$db->drop(name => 'tname'); |
| 439 |
|
| 440 |
=cut |
| 441 |
|
| 442 |
sub drop_table { |
| 443 |
my $self = shift; |
| 444 |
my %parm = @_; |
| 445 |
my $name = $parm{name} or croak "No name specified"; |
| 446 |
|
| 447 |
croak "Database readonly" unless $self->{mode} & (O_CREAT | O_RDWR); |
| 448 |
if (!defined $self->{tables}->{$name}) { |
| 449 |
croak "Table '$name' does not exist"; |
| 450 |
} |
| 451 |
$self->{tables}->{$name}->drop; |
| 452 |
|
| 453 |
if ($self->{uniqueatt}) { |
| 454 |
# recycle attribute names |
| 455 |
for (keys %{$self->{attr}}) { |
| 456 |
delete $self->{attr}->{$_} if $self->{attr}->{$_} eq $name; |
| 457 |
} |
| 458 |
} |
| 459 |
undef $self->{tables}->{$name}; # Call WAIT::Table::DESTROY here; |
| 460 |
1; |
| 461 |
} |
| 462 |
|
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|
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1; |
| 465 |
|
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|
| 467 |
=head1 AUTHOR |
| 468 |
|
| 469 |
Ulrich Pfeifer E<lt>F<pfeifer@ls6.informatik.uni-dortmund.de>E<gt> |
| 470 |
|
| 471 |
=cut |
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|
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