/usr/share/perl5/DBIx/Recordset/DBSeq.pm is in libdbix-recordset-perl 0.26-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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#
# DBIx::Recordset - Copyright (c) 1997-2000 Gerald Richter / ECOS
#
# You may distribute under the terms of either the GNU General Public
# License or the Artistic License, as specified in the Perl README file.
#
# THIS IS BETA SOFTWARE!
#
# THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
# WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
#
# $Id: DBSeq.pm,v 1.5 2000/06/26 05:16:18 richter Exp $
#
###################################################################################
package DBIx::Recordset::DBSeq ;
use strict 'vars' ;
## ----------------------------------------------------------------------------
##
## new
##
## creates a new DBIx::Recordset::DBSeq object.
##
## $dbh = Database handle
## $table = table where to keep sequences
##
sub new
{
my ($class, $dbh, $table, $min, $max) = @_ ;
my $self = {
'*Debug' => $DBIx::Recordset::Debug,
'*dbh' => $dbh,
'*table' => $table,
'*DefaultMin' => $min || 1,
'*DefaultMax' => $max || 'NULL',
} ;
bless ($self, $class) ;
return $self ;
}
## ----------------------------------------------------------------------------
##
## NextVal
##
## get next value from counter
##
## in $name = counter name
##
sub NextVal
{
my ($self, $name) = @_ ;
my $dbh = $self -> {'*dbh'} ;
$dbh -> do ("lock table $self->{'*table'} write") or die "Cannot lock $self->{'*table'} ($DBI::errstr)" ;
my $sth = $dbh -> prepare ("select cnt,maxcnt from $self->{'*table'} where name=?") or die "Cannot prepare select for $self->{'*table'} ($DBI::errstr)" ;
$sth -> execute ($name) ;
my $row = $sth -> fetchrow_arrayref ;
my $cnt ;
my $max ;
if (!$row)
{
$cnt = $self->{'*DefaultMin'} ;
$max = $self->{'*DefaultMax'} ;
my $cnt1 = $cnt + 1 ;
$dbh -> do ("insert into $self->{'*table'} (name,cnt,maxcnt) values ('$name',$cnt1,$max)") or die "Cannot insert $self->{'*table'} ($DBI::errstr)" ;
}
else
{
$cnt = $row -> [0] ;
die "Max count reached for sequence $name" if (defined ($row->[1]) && $cnt+1 > $row->[1]) ;
$dbh -> do ("update $self->{'*table'} set cnt=cnt+1 where name='$name'") or die "Cannot update $self->{'*table'} ($DBI::errstr)" ;
}
$dbh -> do ("unlock table") or die "Cannot unlock $self->{'*table'} ($DBI::errstr)" ;
return $cnt ;
}
1;
__END__
=pod
=head1 NAME
DBIx::Recordset::DBSeq - Sequence generator in DBI database
=head1 SYNOPSIS
use DBIx::Recordset::DBSeq ;
$self = DBIx::Recordset::DBSeq ($dbh, 'sequences', $min, $max) ;
$val1 = $self -> NextVal ('foo') ;
$val2 = $self -> NextVal ('foo') ;
$val3 = $self -> NextVal ('bar') ;
=head1 DESCRIPTION
DBIx::Recordset::FileSeq generates unique numbers. State is kept in the
one table of a database accessible via DBI. With the new constructor you
give an open database handle and specify the the table where state should be kept.
Optionaly you can give a min and
a max values, which will be used for new sequences.
With B<NextVal> you can get the next value
for the sequence of the given name.
The table must created in the following form:
create table
(
name varchar (32),
cnt integer,
maxcnt integer,
primary key name
) ;
If the sequence value reaches the maxcnt value, NextVal will die with an
error message. If maxcnt contains C<null> there is no limit.
=head1 AUTHOR
G.Richter (richter@dev.ecos.de)
=head1 SEE ALSO
=over
=item DBIx::Recordset
=back
=cut
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