NAME
Tangram::IntrSet - map Set::Object using a foreign key
SYNOPSIS
use Tangram;
# or
use Tangram::Core;
use Tangram::IntrSet;
$schema = Tangram::Schema->new(
classes => { Basket => { fields => {
iset =>
{
# long form
fruits =>
{
class => 'Fruit',
coll => 'basket',
},
# or (short form)
fruits => 'Fruit',
}
DESCRIPTION
This class maps references to Set::Object collections in an intrusive fashion. The persistent fields are grouped in a hash under the iset
key in the field hash.
The set may contain only objects of persistent classes. These classes must have a common persistent base class.
Tangram uses a column on the element's table to store the id of the object containing the collection.
CAUTION: the same object may not be an element of the same collection, in two different objects. This mapping may be used only for one-to-many relationships.
The field names are passed in a hash that associates a field name with a field descriptor. The field descriptor may be either a hash or a string. The hash uses the following fields:
class
coll
back
Mandatory field class
specifies the class of the elements.
Optional field coll
sets the name the column containing the id of the containing object. This defaults to 'C_m', where 'C' is the class of the containing object, and 'm' is the field name.
Optional field back
sets the name of a field that is inserted in the elements. That field acts as a demand-loaded, read-only reference to the object containing the collection.
If the descriptor is a string, it is interpreted as the name of the element's class. This is equivalent to specifying only the class
field in the hash variant.