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
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
Initialize the association_dependencies hash for this model.
# 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
Call add_association_dependencies with any dependencies given in the plugin call.
# File lib/sequel/plugins/association_dependencies.rb 39 def self.configure(model, hash=OPTS) 40 model.add_association_dependencies(hash) unless hash.empty? 41 end