Rose::DB::Object::MakeMethods::Std - Create object methods related to
Rose::DB::Object::Std-derived objects.
package Category;
our @ISA = qw(Rose::DB::Object::Std);
...
package Color;
our @ISA = qw(Rose::DB::Object::Std);
...
package Product;
our @ISA = qw(Rose::DB::Object);
...
use Rose::DB::Object::MakeMethods::Std
(
object_by_id =>
[
color => { class => 'Color' },
category =>
{
class => 'Category',
id_method => 'cat_id',
share_db => 0,
},
],
);
...
$prod = Product->new(...);
$color = $prod->color;
# $prod->color call is roughly equivalent to:
#
# $color = Color->new(id => $prod->color_id,
# db => $prod->db);
# $ret = $color->load;
# return $ret unless($ret);
# return $color;
$cat = $prod->category;
# $prod->category call is roughly equivalent to:
#
# $cat = Category->new(id => $prod->cat_id);
# $ret = $cat->load;
# return $ret unless($ret);
# return $cat;
"Rose::DB::Object::MakeMethods::Std" creates
methods related to Rose::DB::Object::Std-derived objects. It inherits from
Rose::Object::MakeMethods. See the Rose::Object::MakeMethods documentation to
learn about the interface. The method types provided by this module are
described below.
All method types defined by this module are designed to work with
objects that are subclasses of (or otherwise conform to the interface of)
Rose::DB::Object. In particular, the object is expected to have a
"db" method that returns a
Rose::DB-derived object. See the Rose::DB::Object::Std documentation for
more details.
- object_by_id
- Create a get/set methods for a single Rose::DB::Object::Std-derived object
loaded based on a primary key stored in an attribute of the current
object.
- Options
- "class"
- The name of the Rose::DB::Object::Std-derived class of the object to be
loaded. This option is required.
- "hash_key"
- The key inside the hash-based object to use for the storage of the object.
Defaults to the name of the method.
- "id_method"
- The name of the method that contains the primary key of the object to be
loaded. Defaults to the method name concatenated with
"_id".
- "interface"
- Choose the interface. The only current interface is
"get_set", which is the default.
- "share_db"
- If true, the "db" attribute of the
current object is shared with the object loaded. Defaults to true.
- Interfaces
- "get_set"
- Creates a method that will attempt to create and load a
Rose::DB::Object::Std-derived object based on a primary key stored in an
attribute of the current object.
If passed a single argument of undef, the
"hash_key" used to store the object is
set to undef. Otherwise, the argument is assumed to be an object of type
"class" and is assigned to
"hash_key" after having its primary
key set to the corresponding value in the current object.
If called with no arguments and the
"hash_key" used to store the object is
defined, the object is returned. Otherwise, the object is created and
loaded.
The load may fail for several reasons. The load will not even
be attempted if the primary key attribute in the current object is
undefined. Instead, undef will be returned. If the call to the newly
created object's "load" method returns
false, that false value is returned.
If the load succeeds, the object is returned.
Example:
package Category;
our @ISA = qw(Rose::DB::Object::Std);
...
package Color;
our @ISA = qw(Rose::DB::Object::Std);
...
package Product;
our @ISA = qw(Rose::DB::Object);
...
use Rose::DB::Object::MakeMethods::Std
(
object_by_id =>
[
color => { class => 'Color' },
category =>
{
class => 'Category',
id_method => 'cat_id',
share_db => 0,
},
],
);
...
$prod = Product->new(...);
$color = $prod->color;
# $prod->color call is roughly equivalent to:
#
# $color = Color->new(id => $prod->color_id,
# db => $prod->db);
# $ret = $color->load;
# return $ret unless($ret);
# return $color;
$cat = $prod->category;
# $prod->category call is roughly equivalent to:
#
# $cat = Category->new(id => $prod->cat_id);
# $ret = $cat->load;
# return $ret unless($ret);
# return $cat;
John C. Siracusa (siracusa@gmail.com)
Copyright (c) 2010 by John C. Siracusa. All rights reserved. This program is
free software; you can redistribute it and/or modify it under the same terms
as Perl itself.