NAME

DBIx::Class::VirtualColumns - Add virtual columns to DBIx::Class schemata

SYNOPSIS

package Your::Schema::Class;
use strict;
use warnings;

use base 'DBIx::Class';

__PACKAGE__->load_components(
  "VirtualColumns",
  "PK",
  "Core",
);

__PACKAGE__->table("sometable");
__PACKAGE__->add_columns(qw/dbcol1 dbcol2/);
__PACKAGE__->add_virtual_columns(qw/vcol1 vcol2 vcol3/);

# =========================================================
# Somewhere else

my $item = $schema->resultset('Artist')->find($id);
$item->vcol1('test'); # Set 'test'
$item->get_column('vcol1'); # Return 'test'

my $otheritem = $schema->resultset('Artist')->create({
    dbcol1 => 'value1',
    dbcol2 => 'value2',
    vcol1  => 'value3',
    vcol2  => 'value4',
});

$otheritem->vcol1(); # Now is 'value3'

# Get the column metadata just like for a regular DBIC column
my $info = $result_source->column_info('vcol1');

DESCRIPTION

This module allows to specify 'virtual columns' in DBIx::Class schema classes. Virtual columns behave almost like regular columns but are not stored in the database. They may be used to store temporary information in the DBIx::Class::Row object and without introducting an additional interface.

Most DBIx::Class methods like set_column, set_columns, get_column, get_columns, column_info, ... will work with regular as well as virtual columns.

USAGE

Use this module if you want to add 'virtual' columns to a DBIC class which behave like real columns (e.g. if you want to use the set_column, get_column methods)

However if you only want to add non-column data to DBIx::Class::Row objects, then there are easier/better ways:

__PACKAGE__->mk_group_accessors(simple => qw(foo bar baz));

METHODS

add_virtual_columns

Adds virtual columns to the result source. If supplied key => hashref pairs, uses the hashref as the column_info for that column. Repeated calls of this method will add more columns, not replace them.

$table->add_virtual_columns(qw/column1 column2/); 
OR 
$table->add_virtual_columns(column1 => \%column1_info, column2 => \%column2_info, ...); 

The column names given will be created as accessor methods on your DBIx::Class::Row objects, you can change the name of the accessor by supplying an "accessor" in the column_info hash.

The following options are currently recognised/used by DBIx::Class::VirtualColumns:

  • accessor

    Use this to set the name of the accessor method for this column. If not set, the name of the column will be used.

add_virtual_column

Shortcut for add_virtual_columns

has_any_column

Returns true if the source has a virtual or regular column of this name, false otherwise.

has_virtual_column

Returns true if the source has a virtual column of this name, false otherwise.

remove_virtual_columns

$table->remove_columns(qw/col1 col2 col3/);
 

Removes virtual columns from the result source.

remove_virtual_column

Shortcut for remove_virtual_columns

_virtual_filter

Splits attributes for regular and virtual columns

new

Overloaded method. "new" in DBIx::Class::Row

get_column

Overloaded method. "get_colum" in DBIx::Class::Row

get_columns

Overloaded method. "get_colums" in DBIx::Class::Row

store_column

Overloaded method. "store_column" in DBIx::Class::Row

set_column

Overloaded method. "set_column" in DBIx::Class::Row

columns_info

Overloaded method. "columns_info" in DBIx::Class::ResultSource

Additionally returns the HASH key 'virtual' which indicates if the requested column is virtual or not.

update

Overloaded method. "update" in DBIx::Class::Row

CAVEATS

The best way to add non-column data to DBIC objects is to use Class::Accessor::Grouped.

__PACKAGE__->mk_group_accessors(simple => qw(foo bar baz));

Use DBIx::Class::VirtualColumns only if you rely on DBIx::Class::Row methods like set_column, get_column, ...

SUPPORT

This module was just a proof of concept, and is not actively developed anymore. Patches are still welcome though.

Please report any bugs to bug-dbix-class-virtualcolumns@rt.cpan.org, or through the web interface at http://rt.cpan.org/Public/Bug/Report.html?Queue=DBIx::Class::VirtualColumns. I will be notified, and then you'll automatically be notified of progress on your report as I make changes.

AUTHOR

Maroš Kollár
CPAN ID: MAROS
maros [at] k-1.com
L<http://www.revdev.at>

ACKNOWLEDGEMENTS

This module was written for Revdev http://www.revdev.at, a nice litte software company I run with Koki and Domm (http://search.cpan.org/~domm/).

COPYRIGHT

DBIx::Class::VirtualColumns is Copyright (c) 2008 Maroš Kollár - http://www.revdev.at

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

The full text of the license can be found in the LICENSE file included with this module.