module Sequel::Plugins::AssociationDependencies
The AssociationDependencies plugin allows you do easily set up before and/or after destroy hooks for destroying, deleting, or nullifying associated model objects. The following association types support the following dependency actions:
-
:many_to_many - :nullify (removes all related entries in join table)
-
:many_to_one - :delete, :destroy
-
:one_to_many, one_to_one - :delete, :destroy, :nullify (sets foreign key to NULL for all associated objects)
This plugin works directly with the association datasets and does not use any cached association values. The :delete action will delete all associated objects from the database in a single SQL call. The :destroy action will load each associated object from the database and call the destroy method on it.
To set up an association dependency, you must provide a hash with association name symbols and dependency action values. You can provide the hash to the plugin call itself or to the add_association_dependencies method:
Business.plugin :association_dependencies, :address=>:delete # or: Artist.plugin :association_dependencies Artist.add_association_dependencies :albums=>:destroy, :reviews=>:delete, :tags=>:nullify
Constants
- ASSOCIATION_MAPPING
Mapping of association types to when the dependency calls should be made (either :before for in before_destroy or :after for in after_destroy)
- DEPENDENCE_ACTIONS
The valid dependence actions
Public Class Methods
Initialize the association_dependencies hash for this model.
# File lib/sequel/plugins/association_dependencies.rb, line 34 def self.apply(model, hash=OPTS) model.instance_eval{@association_dependencies = {:before_delete=>[], :before_destroy=>[], :before_nullify=>[], :after_delete=>[], :after_destroy=>[]}} end
Call add_association_dependencies with any dependencies given in the plugin call.
# File lib/sequel/plugins/association_dependencies.rb, line 39 def self.configure(model, hash=OPTS) model.add_association_dependencies(hash) unless hash.empty? end