Taro
2008-May-31 15:29 UTC
How do you figure out that a Parent model is trying to destroy it''s children?
I have a simple acts_as_list model structure where the Language holds
a lot of Wikis. I want to validate inside Wikis so as to not destroy
the last Wiki in a Language. However, when the Language is destroyed,
I want all the wikis associated with the Language to destroy
themselves.
The solution seemed simple until I figured out that when I try to
destroy a Language, the method fails at destroying the last Wiki.
This is because I am trying to destroy the last Wiki in the Language.
I need to, therefore, figure out a way to bypass the "last wiki
validations" ONLY when I''m destroying a Language. Is there a
conditional or a flag that lets me figure out that the parent is
trying to destroy the children?
Here''s my code, by the way:
----
class Language < ActiveRecord::Base
#indicate this is an array
has_many :wikis,
:order => :position,
:dependent => :destroy
#everything has to be unique!
validates_presence_of :language
validates_presence_of :url_id
validates_uniqueness_of :language
validates_uniqueness_of :url_id
validates_length_of :url_id,
:in => 2..5
validates_format_of :url_id,
:with => /^[a-z]{2}([a-z_]{0,2}[a-z])?$/
def after_update
if self.id == 1 and self.url_id != ''en''
raise "Cannot change this language''s url!"
end
end
def after_destroy
if self.url_id == ''en''
raise "Cannot delete this language!"
end
end
end
----
class Wiki < ActiveRecord::Base
#indicate this is array elements
belongs_to :language
acts_as_list :scope => :language_id
#general limits:
validates_presence_of :title
validates_format_of :title, :with => /^\w.+$/ #letter-first
validates_uniqueness_of :title, :scope => :language_id
validates_presence_of :body
validates_length_of :body, :minimum => 10
def after_destroy
if self.id == 1
raise "Cannot delete this Wiki!"
elsif ( Language.find( self.language_id ) ).wikis.empty?
raise "Cannot delete the last Wiki!"
end
end
end
----
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Sav
2008-May-31 18:13 UTC
Re: How do you figure out that a Parent model is trying to destroy it''s children?
You can define what happens to dependents in your Language model... has_many :wikis, :dependent => :delete_all If you don''t want to :delete_all, you could simply :nullify On May 31, 8:29 am, Taro <japtar10...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I have a simple acts_as_list model structure where the Language holds > a lot of Wikis. I want to validate inside Wikis so as to not destroy > the last Wiki in a Language. However, when the Language is destroyed, > I want all the wikis associated with the Language to destroy > themselves. > > The solution seemed simple until I figured out that when I try to > destroy a Language, the method fails at destroying the last Wiki. > This is because I am trying to destroy the last Wiki in the Language. > I need to, therefore, figure out a way to bypass the "last wiki > validations" ONLY when I''m destroying a Language. Is there a > conditional or a flag that lets me figure out that the parent is > trying to destroy the children? > > Here''s my code, by the way: > ---- > class Language < ActiveRecord::Base > #indicate this is an array > has_many :wikis, > :order => :position, > :dependent => :destroy > > #everything has to be unique! > validates_presence_of :language > validates_presence_of :url_id > validates_uniqueness_of :language > validates_uniqueness_of :url_id > validates_length_of :url_id, > :in => 2..5 > validates_format_of :url_id, > :with => /^[a-z]{2}([a-z_]{0,2}[a-z])?$/ > > def after_update > if self.id == 1 and self.url_id != ''en'' > raise "Cannot change this language''s url!" > end > end > > def after_destroy > if self.url_id == ''en'' > raise "Cannot delete this language!" > end > end > end > ---- > class Wiki < ActiveRecord::Base > #indicate this is array elements > belongs_to :language > acts_as_list :scope => :language_id > > #general limits: > validates_presence_of :title > validates_format_of :title, :with => /^\w.+$/ #letter-first > validates_uniqueness_of :title, :scope => :language_id > validates_presence_of :body > validates_length_of :body, :minimum => 10 > > def after_destroy > if self.id == 1 > raise "Cannot delete this Wiki!" > elsif ( Language.find( self.language_id ) ).wikis.empty? > raise "Cannot delete the last Wiki!" > end > end > end > ------~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Taro
2008-May-31 18:41 UTC
Re: How do you figure out that a Parent model is trying to destroy it''s children?
Huh. I didn''t know delete bypasses the validations methods. Thank a lot! On May 31, 2:13 pm, Sav <savar...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> You can define what happens to dependents in your Language model... > > has_many :wikis, :dependent => :delete_all > > If you don''t want to :delete_all, you could simply :nullify > > On May 31, 8:29 am, Taro <japtar10...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > I have a simple acts_as_list model structure where the Language holds > > a lot of Wikis. I want to validate inside Wikis so as to not destroy > > the last Wiki in a Language. However, when the Language is destroyed, > > I want all the wikis associated with the Language to destroy > > themselves. > > > The solution seemed simple until I figured out that when I try to > > destroy a Language, the method fails at destroying the last Wiki. > > This is because I am trying to destroy the last Wiki in the Language. > > I need to, therefore, figure out a way to bypass the "last wiki > > validations" ONLY when I''m destroying a Language. Is there a > > conditional or a flag that lets me figure out that the parent is > > trying to destroy the children? > > > Here''s my code, by the way: > > ---- > > class Language < ActiveRecord::Base > > #indicate this is an array > > has_many :wikis, > > :order => :position, > > :dependent => :destroy > > > #everything has to be unique! > > validates_presence_of :language > > validates_presence_of :url_id > > validates_uniqueness_of :language > > validates_uniqueness_of :url_id > > validates_length_of :url_id, > > :in => 2..5 > > validates_format_of :url_id, > > :with => /^[a-z]{2}([a-z_]{0,2}[a-z])?$/ > > > def after_update > > if self.id == 1 and self.url_id != ''en'' > > raise "Cannot change this language''s url!" > > end > > end > > > def after_destroy > > if self.url_id == ''en'' > > raise "Cannot delete this language!" > > end > > end > > end > > ---- > > class Wiki < ActiveRecord::Base > > #indicate this is array elements > > belongs_to :language > > acts_as_list :scope => :language_id > > > #general limits: > > validates_presence_of :title > > validates_format_of :title, :with => /^\w.+$/ #letter-first > > validates_uniqueness_of :title, :scope => :language_id > > validates_presence_of :body > > validates_length_of :body, :minimum => 10 > > > def after_destroy > > if self.id == 1 > > raise "Cannot delete this Wiki!" > > elsif ( Language.find( self.language_id ) ).wikis.empty? > > raise "Cannot delete the last Wiki!" > > end > > end > > end > > ------~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---