Rails - Sep 2006 - @article.article_groups.delete_if... Dosn't work!

If I try:

      @article.article_groups.delete_if {|x|
        x.group_id == x.group_id
      }

It does nothing.

If I try:

      articletmp.article_groups.each{ |x|
              @article.article_groups.delete(y)
}

It deletes some of the groups.

@article.article_groups.clear
works.

Why dosn''t the to first examples work as expected??

Do I have to put groups I don''t want to be deleted inn as hidden
fields in my form? (I of course dosn''t want every groups to be deleted
as in the example above).

- Henrik

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If I try:

      @article.article_groups.delete_if {|x|
        x.group_id == x.group_id
      }

It does nothing.

If I try:

      articletmp.article_groups.each{ |x|
              @article.article_groups.delete(y)
}

It deletes some of the groups.

@article.article_groups.clear
works.

Why dosn''t the to first examples work as expected??

Do I have to put groups I don''t want to be deleted inn as hidden
fields in my form? (I of course dosn''t want every groups to be deleted
as in the example above).

- Henrik

-- 
Posted via http://www.ruby-forum.com/.

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Henrik Ormåsen wrote:
> If I try:
> 
>       @article.article_groups.delete_if {|x|
>         x.group_id == x.group_id
>       }
> 
> It does nothing.
> 
> If I try:
> 
>       articletmp.article_groups.each{ |x|
>               @article.article_groups.delete(y)
> }
> 
> It deletes some of the groups.
> 
> @article.article_groups.clear
> works.
> 
> Why dosn''t the to first examples work as expected??
article_groups is an AssociationCollection, for which
all the usual array methods work.  But only some of these
methods like delete and clear have database side-effects.
The rest operate only on the in-memory array object.

So to make delete_if work on the database objects you
either have to write

@article.article_groups.delete(
   @article.article_groups.select {|x| x.group_id == x.group_id}
)

or

@article.article_groups.each do |x|
   @article.article_groups.delete(x) if x.group_id == x.group_id
end

or put the following in environment.rb

class ActiveRecord::Associations::AssociationCollection
   def delete_if(&block)
     delete( select(&block) )
   end
end

-- 
We develop, watch us RoR, in numbers too big to ignore.


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