Sequel::Plugins::AssociationDependencies

The association_dependencies 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

Methods

Classes and Modules

Constants

ASSOCIATION_MAPPING	=	{:one_to_many=>:before, :many_to_one=>:after, :many_to_many=>:before, :one_to_one=>:before}.freeze		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	=	[:delete, :destroy, :nullify].freeze		The valid dependence actions

Public Class methods

apply(model, hash=OPTS)

Initialize the association_dependencies hash for this model.

[show source]

   # File lib/sequel/plugins/association_dependencies.rb
34 def self.apply(model, hash=OPTS)
35   model.instance_exec{@association_dependencies = {:before_delete=>[], :before_destroy=>[], :before_nullify=>[], :after_delete=>[], :after_destroy=>[]}}
36 end

configure(model, hash=OPTS)

Call add_association_dependencies with any dependencies given in the plugin call.