module Sequel::Plugins::AssociationDependencies

  1. lib/sequel/plugins/association_dependencies.rb

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

Methods

Public Class

  1. apply
  2. configure

Constants

ASSOCIATION_MAPPING = {:one_to_many=>:before, :many_to_one=>:after, :many_to_many=>:before, :one_to_one=>:before}  

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]  

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, line 33
def self.apply(model, hash=OPTS)
  model.instance_eval{@association_dependencies = {:before_delete=>[], :before_destroy=>[], :before_nullify=>[], :after_delete=>[], :after_destroy=>[]}}
end
configure (model, hash=OPTS)

Call add_association_dependencies with any dependencies given in the plugin call.

[show source]
# File lib/sequel/plugins/association_dependencies.rb, line 38
def self.configure(model, hash=OPTS)
  model.add_association_dependencies(hash) unless hash.empty?
end