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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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|
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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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name => <name>, |
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directory => <dir> |
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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 |
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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 = $parm{name}; |
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|
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unless ($name) { |
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croak("No name specified"); |
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} |
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|
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unless (-d $dir){ |
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croak("Directory '$dir' does not exits: $!"); |
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} |
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|
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if (-d "$dir/$name") { |
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warn "Warning: Directory '$dir/$name' already exists"; |
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} else { |
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unless (mkdir "$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->{name} = $name; |
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$self->{dir} = $dir; |
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my $env= BerkeleyDB::Env->new( |
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Home => $self->file, |
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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 => $self->file."/errorlog", |
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); |
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unless ($env) { |
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require Carp; |
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Carp::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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) or die("Cannot open _attr: $BerkeleyDB::Error"); |
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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 $self->file which |
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# is a *directory* and there are no berkeley tables in this |
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# directory, but there is one subdirectory in this directory for |
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# *each* *table* object. |
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|
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$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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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} = $name; |
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my($env); |
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if ($mode & O_RDWR) { |
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my $flags = DB_CREATE|DB_INIT_MPOOL|DB_INIT_CDB; |
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warn "setting flags for envorinment 'writing'"; |
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$env = BerkeleyDB::Env->new( |
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Home => $self->file, |
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Flags => $flags, |
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); |
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unless ($env) { |
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require Carp; |
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Carp::confess("Could not create environment: $BerkeleyDB::Error"); |
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} |
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} else { |
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# in der Datei neo-lieferung.pl habe ich in Punkt 2.6 darueber |
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# lamentiert, dass der Readonly-User kein Environment bekommt. |
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# Es muesste ein Klacks sein, dafuer einen Schalter |
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# bereitzustellen. Kostet mich aber zu viel Denkzeit. |
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# warn "DEBUG: setting env to NIL"; |
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$env = ""; |
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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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or die "Cannot open _attr: $BerkeleyDB::Error; mdbf[$maindbfile] env[$env]"; |
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# warn "DEBUG: opened the database for _attr"; |
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$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) = @_; |
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$self->maindbfile; |
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$self->file; |
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for my $t (values %{$self->{tables} || {}}) { |
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$t->{file} ||= $self->{file}; |
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$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->{file} ||= $self->{file}; |
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$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->{file} ||= $self->{file}; |
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$ind->{maindbfile} ||= $self->{maindbfile}; |
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$ind->{mode} = $self->{mode}; |
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} |
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} |
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} |
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} |
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|
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=head2 C<$db-E<gt>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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=cut |
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|
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sub dispose { |
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my $dir; |
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|
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if (ref $_[0]) { # called with instance |
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croak "Database readonly" unless $_[0]->{mode} & (O_CREAT | O_RDWR); |
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$dir = $_[0]->file; |
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$_[0]->close; |
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} else { |
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my $type = shift; |
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my %parm = @_; |
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my $base = $parm{directory} || '.'; |
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my $name = $parm{name} || croak "No name specified"; |
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$dir = "$base/$name"; |
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} |
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croak "No such database '$dir'" unless -e "$dir/meta"; |
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|
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#warn "Running rmtree on dir[$dir]"; |
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my $ret = rmtree($dir, 0, 1); |
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#warn "rmtree returned[$ret]"; |
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$ret; |
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} |
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|
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|
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=head2 C<$db-E<gt>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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=cut |
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|
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sub close { |
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my $self = $_[0]; |
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my $did_save; |
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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 = delete $self->{env}; # core dump land |
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my $db = delete $self->{_attr}; # core dump land |
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for my $att (qw(file maindbfile name)) { |
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delete $self->{$att}; |
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} |
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|
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my $dat = nfreeze $self; |
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$db->db_put(0, $dat); |
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|
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warn "DEBUG: Removing env[$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 $_[0]; |
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$did_save; |
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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 $file = $self->file; |
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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(file => "$file/$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, $name); |
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} |
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|
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sub maindbfile { |
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my($self,$file) = @_; |
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return $self->{maindbfile} if $self->{maindbfile}; |
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$file ||= $self->file; |
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die "ALERT: no file argument, no file attribute???" unless $file; |
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$self->{maindbfile} = "$file/etat"; |
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} |
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|
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sub file { |
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my($self) = @_; |
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return $self->{file} if $self->{file}; |
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require Carp; |
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Carp::confess("no attribut dir?") unless $self->{dir}; |
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Carp::confess("no attribut name?") unless $self->{name}; |
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$self->{file} = "$self->{dir}/$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 $self = shift; |
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|
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for (values %{$self->{tables}}) { |
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$_->sync; |
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} |
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} |
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|
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sub table { |
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my $self = shift; |
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my %parm = @_; |
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my $name = $parm{name} or croak "No name specified"; |
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|
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if (defined $self->{tables}->{$name}) { |
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if (exists $parm{mode}) { |
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$self->{tables}->{$name}->{mode} = $parm{mode}; |
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} else { |
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$self->{tables}->{$name}->{mode} = $self->{mode}; |
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} |
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WAIT::Table::Handle->new($self,$name); |
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} else { |
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croak "No such table '$name'"; |
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} |
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} |
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|
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|
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=head2 C<$db-E<gt>drop(name =E<gt>> I<tname>C<);> |
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|
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Drop the table named I<tname>. The table should be closed before |
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calling B<drop>. |
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|
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=cut |
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|
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sub drop_table { |
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my $self = shift; |
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my %parm = @_; |
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my $name = $parm{name} or croak "No name specified"; |
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|
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croak "Database readonly" unless $self->{mode} & (O_CREAT | O_RDWR); |
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if (!defined $self->{tables}->{$name}) { |
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croak "Table '$name' does not exist"; |
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} |
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$self->{tables}->{$name}->drop; |
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|
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if ($self->{uniqueatt}) { |
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# recycle attribute names |
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for (keys %{$self->{attr}}) { |
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delete $self->{attr}->{$_} if $self->{attr}->{$_} eq $name; |
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} |
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} |
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undef $self->{tables}->{$name}; # Call WAIT::Table::DESTROY here; |
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1; |
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} |
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|
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|
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1; |
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|
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|
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=head1 AUTHOR |
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|
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Ulrich Pfeifer E<lt>F<pfeifer@ls6.informatik.uni-dortmund.de>E<gt> |
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|
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=cut |
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|
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