NAME¶
Rose::DB::Object::Metadata::Relationship::OneToMany - One to many table
relationship metadata object.
SYNOPSIS¶
use Rose::DB::Object::Metadata::Relationship::OneToMany;
$rel = Rose::DB::Object::Metadata::Relationship::OneToMany->new(...);
$rel->make_methods(...);
...
DESCRIPTION¶
Objects of this class store and manipulate metadata for relationships in which a
single row from one table refers to multiple rows in another table.
This class inherits from Rose::DB::Object::Metadata::Relationship. Inherited
methods that are not overridden will not be documented a second time here. See
the Rose::DB::Object::Metadata::Relationship documentation for more
information.
METHOD MAP¶
- "count"
- Rose::DB::Object::MakeMethods::Generic, objects_by_key, "interface
=> 'count'" ...
- "find"
- Rose::DB::Object::MakeMethods::Generic, objects_by_key, "interface
=> 'find'" ...
- "iterator"
- Rose::DB::Object::MakeMethods::Generic, objects_by_key, "interface
=> 'iterator'" ...
- "get_set"
- Rose::DB::Object::MakeMethods::Generic, objects_by_key, "interface
=> 'get_set'" ...
- "get_set_now"
- Rose::DB::Object::MakeMethods::Generic, objects_by_key, "interface
=> 'get_set_now'" ...
- "get_set_on_save"
- Rose::DB::Object::MakeMethods::Generic, objects_by_key, "interface
=> 'get_set_on_save'" ...
- "add_now"
- Rose::DB::Object::MakeMethods::Generic, objects_by_key, "interface
=> 'add_now'" ...
- "add_on_save"
- Rose::DB::Object::MakeMethods::Generic, objects_by_key, "interface
=> 'add_on_save'" ...
See the Rose::DB::Object::Metadata::Relationship documentation for an
explanation of this method map.
CLASS METHODS¶
- default_auto_method_types [TYPES]
- Get or set the default list of auto_method_types. TYPES should be a list
of relationship method types. Returns the list of default relationship
method types (in list context) or a reference to an array of the default
relationship method types (in scalar context). The default list contains
"find", "get_set_on_save", and
"add_on_save".
OBJECT METHODS¶
- build_method_name_for_type TYPE
- Return a method name for the relationship method type TYPE.
For the method types "get_set", "get_set_now", and
"get_set_on_save", the relationship's name is returned.
For the method types "add_now" and "add_on_save", the
relationship's name prefixed with "add_" is returned.
For the method type "find", the relationship's name prefixed with
"find_" is returned.
For the method type "count", the relationship's name suffixed with
"_count" is returned.
For the method type "iterator", the relationship's name suffixed
with "_iterator" is returned.
Otherwise, undef is returned.
- is_singular
- Returns false.
- manager_class [CLASS]
- Get or set the name of the Rose::DB::Object::Manager-derived class used to
fetch objects. The make_methods method will use Rose::DB::Object::Manager
if this value is left undefined.
Note: when the name of a relationship that has
"manager_args" is used in a Rose::DB::Object::Manager
with_objects or require_objects parameter value, only the sort_by
argument will be copied from "manager_args" and incorporated
into the query.
- manager_method [METHOD]
- Get or set the name of the manager_class class method to call when
fetching objects. The make_methods method will use get_objects if this
value is left undefined.
- manager_count_method [METHOD]
- Get or set the name of the manager_class class method to call when
counting objects. The make_methods method will use get_objects_count if
this value is left undefined.
- manager_iterator_method [METHOD]
- Get or set the name of the manager_class class method to call when
creating an iterator. The make_methods method will use
get_objects_iterator if this value is left undefined.
- manager_args [HASHREF]
- Get or set a reference to a hash of name/value arguments to pass to the
manager_method when fetching objects. For example, this can be used to
enforce a particular sort order for objects fetched via this relationship.
For example:
Product->meta->add_relationship
(
code_names =>
{
type => 'one to many',
class => 'CodeName',
column_map => { id => 'product_id' },
manager_args =>
{
sort_by => CodeName->meta->table . '.name',
},
},
);
This would ensure that a "Product"'s "code_names()" are
listed in alphabetical order. Note that the "name" column is
prefixed by the name of the table fronted by the "CodeName"
class. This is important because several tables may have a column named
"name." If this relationship is used to form a JOIN in a query
along with one of those tables, then the "name" column will be
ambiguous. Adding a table name prefix disambiguates the column name.
Also note that the table name is not hard-coded. Instead, it is fetched from
the Rose::DB::Object-derived class that fronts the table. This is more
verbose, but is a much better choice than including the literal table name
when it comes to long-term maintenance of the code.
See the documentation for Rose::DB::Object::Manager's get_objects method for
a full list of valid arguments for use with the "manager_args"
parameter, but remember that you can define your own custom manager_class
and thus can also define what kinds of arguments "manager_args"
will accept.
- map_column LOCAL [, FOREIGN]
- If passed a local column name LOCAL, return the corresponding column name
in the foreign table. If passed both a local column name LOCAL and a
foreign column name FOREIGN, set the local/foreign mapping and return the
foreign column name.
- column_map [HASH | HASHREF]
- Get or set a reference to a hash that maps local column names to foreign
column names.
- query_args [ARRAYREF]
- Get or set a reference to an array of query arguments to add to the query
passed to the manager_method when fetching objects.
- type
- Returns "one to many".
AUTHOR¶
John C. Siracusa (siracusa@gmail.com)
LICENSE¶
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.