Example::DB - Example class for DBIx::AnyDBD usage

DBIx-AnyDBD documentation Contained in the DBIx-AnyDBD distribution.

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NAME

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Example::DB - Example class for DBIx::AnyDBD usage

SYNOPSIS

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  use Example::DB
  Example::DB->set_dsn('dbi:Pg:dbname=foo');
  Example::DB->set_user('matt');
  Example::DB->set_password('blueberry');

  my $db = Example::DB->instance();

  my @users = $db->get_users(); # called from Example/DB/Pg.pm

  # NB: This is just an example. It is designed not for usage,
  #     but so that you read the source code!

DESCRIPTION

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This is a couple of example class files that you can use and adapt in projects that use DBIx::AnyDBD. It is here as an example only, and not meant to be used as-is. That means you should copy the code into your own class hierarchy, rather than use it as Example::*.

The methods of most interest are those in DB/*.pm. These implement the database specific routines for each database. They encapsulate various things about each database, such as the ability to do nested transactions, how to retrieve the current id value for a table, and how dates are encapsulated. For most purposes you should put your SQL inside the Default.pm file, and only put stuff in the database specific files when necessary.

Most of the code in these files is originally by Dave Rolsky, with thanks.

DBIx-AnyDBD documentation Contained in the DBIx-AnyDBD distribution. 
# $Id: DB.pm,v 1.2 2002/01/08 11:15:28 matt Exp $

package Example::DB;
use strict;

use DBIx::AnyDBD 1.98;

use vars qw($DB);
use constant MAX_ATTEMPTS => 32;

# class attributes
foreach my $att ( qw( dsn user password connect_attributes ) )
{
    eval "
{
        my \$$att;
        sub set_$att {
                shift; # class name
                \$$att = shift;
        }
        sub $att {
                return \$$att;
        }
}
";
}

sub instance {
    if ($DB && $DB->ping) {
        # rollback uncommited transactions
        # this doesn't work where multiple nested method calls might call instance()
        # $DB->rollback;
        
        return $DB;
    }

    my $class = shift;
    
    my $x = 0;
    do {
	if ($DB) {
            eval { $DB->disconnect; };
            undef $DB;
	}
        $class->connect;
        return $DB if $DB && $DB->ping
    } until ($x++ > MAX_ATTEMPTS);

    die "Couldn't connect to database";
}

sub connect {
    my $class = shift;

    $DB = DBIx::AnyDBD->new( dsn => $class->dsn,
			   user => $class->user,
			   pass => $class->password,
			   attr => $class->connect_attributes,
			   package => $class,
			 );
}

sub DESTROY {
    $DB->disconnect if $DB && ref $DB;
}

1;

__END__