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Payam Fard

2005-Jun-21 03:31 UTC

Activerecord Many-to-many create question

Hi all,

I have a Resources and Assignments table with
many-to-many relationship.

In order to create a new assignment, here is what I do
in my controller class:

@assignment = Assignment.new(@params[:assignment])
resource = Resource.find(:first, :condition =>
"id=#{session[''resource_id'']}")
@assignment.resource[0] = resource

if @assignment.save
  logger.info("Successful creation")
else
  logger.info("Unsuccessful creation")
end

For some reason, the @assignment.save call is
returning false and it does not save anything.
Basically I have a form that includes all the fields
for a new assignment. Once the user submits the
request, it would call the above code to get the
associated resource which is logged into the system.
It is supposed to assign that resource to the newly
created assignment and the save the new assignment
along with an entry into the join
table(resources_assignments) table.

Any ideas on what is wrong with the code snippet above
and how I can fix it would be greatly appreciate it.

Thanks in advance,
Payam.


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Duane Johnson

2005-Jun-21 03:47 UTC

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Re: Activerecord Many-to-many create question

I''m not sure exactly what the problem is, but here are some thoughts  
on the code you posted:
> @assignment = Assignment.new(@params[:assignment])
> resource = Resource.find(:first, :condition =>
> "id=#{session[''resource_id'']}")
I think you should also be able to use this to simplify:
resource = Resource.find(session[''resource_id''])
> @assignment.resource[0] = resource
>The above line looks a little fishy to me (I''ve never used a  
collection like that).  I would do this instead:
@assignment.resources << resource
> if @assignment.save
>   logger.info("Successful creation")
> else
>   logger.info("Unsuccessful creation")
> end
>If you want to see exactly why it''s failing to save, try  
@assignment.save! which will raise an error for you so you can see  
why it failed.
> Thanks in advance,
> Payam.
Good luck,
Duane Johnson
(canadaduane)

Alex Ezell

2005-Jun-21 04:07 UTC

head link

Re: Activerecord Many-to-many create question

Payam Fard wrote:
>Any ideas on what is wrong with the code snippet above
>and how I can fix it would be greatly appreciate it.
>  
>I wonder if since the @assignment.save is what is failing if the problem 
is not necessarily related to the relationship.

However, I did notice that you said your table was called 
"resources_assignments" I believe it should actually be 
"assignments_resources" as the names should be in alphabetical order,
I
think. Then you can check that table to see if anything is getting 
inserted before the @assignment.save.

Try using the code Duane posted and fix the table naming issue and then 
see what kinds of errors or successes you have and we can take another 
look at it. I battled with a many-to-many relationship and its code for 
quite a while, so I know that it can be confusing.

-- 
Alex Ezell

Payam Fard

2005-Jun-21 15:00 UTC

head link

Re: Activerecord Many-to-many create question

Thanks for your reply. Here is how I have changed my
code, even though there is still no change to the
outcome of my program. @assignment.save! is not
throwing any exceptions or errors either. Here is the
modified version. Evertime I submit, I would go to the
else. I made a mistake in my original post, my join
table is called assignments_resources. When I print
the contents of assignment, I am getting the correct
values as well as the associated resource.

  def create
    @assignment = Assignment.new(@params[:assignment])
    resource = Resource.find(session[''resource_id''])
    @assignment.resources << resource
    logger.warn(@assignment)
    if @assignment.save!
      logger.warn("Inside if of assignment.save!!!")
      redirect_to :action => ''list''
    else
      logger.warn("Inside else of assignment.save!!!")
      render_action ''new''
    end
  end

Thanks,
Payam.


--- Duane Johnson <duane.johnson-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> I''m not sure exactly what the problem is, but here
> are some thoughts  
> on the code you posted:
> 
> > @assignment = Assignment.new(@params[:assignment])
> > resource = Resource.find(:first, :condition =>
> > "id=#{session[''resource_id'']}")
> 
> I think you should also be able to use this to
> simplify:
> resource = Resource.find(session[''resource_id''])
> 
> > @assignment.resource[0] = resource
> >
> The above line looks a little fishy to me (I''ve
> never used a  
> collection like that).  I would do this instead:
> @assignment.resources << resource
> 
> > if @assignment.save
> >   logger.info("Successful creation")
> > else
> >   logger.info("Unsuccessful creation")
> > end
> >
> If you want to see exactly why it''s failing to save,
> try  
> @assignment.save! which will raise an error for you
> so you can see  
> why it failed.
> 
> > Thanks in advance,
> > Payam.
> 
> Good luck,
> Duane Johnson
> (canadaduane)
> 
> 
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
> 

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Duane Johnson

2005-Jun-21 15:25 UTC

head link

Re: Activerecord Many-to-many create question

On Jun 21, 2005, at 9:00 AM, Payam Fard wrote:> Thanks for your reply. Here is how I have changed my
> code, even though there is still no change to the
> outcome of my program. @assignment.save! is not
> throwing any exceptions or errors either. Here is the
Hmmm, seems strange.  What do your models look like?

Duane Johnson
(canadaduane)

Payam Fard

2005-Jun-21 15:44 UTC

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Re: Activerecord Many-to-many create question

Here is my model:

class Assignment < ActiveRecord::Base
  has_and_belongs_to_many :resources
end

class Resource < ActiveRecord::Base
  has_and_belongs_to_many :assignments
end

--- Duane Johnson <duane.johnson-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> On Jun 21, 2005, at 9:00 AM, Payam Fard wrote:
> > Thanks for your reply. Here is how I have changed
> my
> > code, even though there is still no change to the
> > outcome of my program. @assignment.save! is not
> > throwing any exceptions or errors either. Here is
> the
> 
> Hmmm, seems strange.  What do your models look like?
> 
> Duane Johnson
> (canadaduane)
> 
> 
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
> 

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Payam Fard

2005-Jun-21 18:48 UTC

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How to write insertion sql to the logs

Hi all,

I am having a problem with inserting a new record into
a table with many-to-many relationship with another
table.

For some reason, my call to save and save! fail. I am
looking at the development.log file, but I do not see
the insert sql that ActiveRecord is trying to execute.
I am getting other stuff written to the logs, but it
looks like it does not write everything.

Is there any way to have ActiveRecord write this sql
into the log to facilitate debugging my problem? Is
there a setting I can play around with to have it
write more things to the log?

Thanks in advance,
Payam.



		
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Duane Johnson

2005-Jun-21 21:20 UTC

head link

Re: Activerecord Many-to-many create question

On Jun 21, 2005, at 9:00 AM, Payam Fard wrote:
> Thanks for your reply. Here is how I have changed my
> code, even though there is still no change to the
> outcome of my program. @assignment.save! is not
> throwing any exceptions or errors either. Here is the
> modified version. Evertime I submit, I would go to the
> else. I made a mistake in my original post, my join
> table is called assignments_resources. When I print
> the contents of assignment, I am getting the correct
> values as well as the associated resource.
>
>   def create
>     @assignment = Assignment.new(@params[:assignment])
Here''s the issue: you need to save your @assignment object before you  
add the resource.  Otherwise, there is no @assignment.id that your  
resource.assignment_id can be set to.  Perhaps you could re-arrange  
your method, or else use Assignment.create instead.   
(Assignment.create would do the same thing as Assignment.new.save).
>     resource = Resource.find(session[''resource_id''])
>     @assignment.resources << resource
>     logger.warn(@assignment)
>     if @assignment.save!
>       logger.warn("Inside if of assignment.save!!!")
>       redirect_to :action => ''list''
>     else
>       logger.warn("Inside else of assignment.save!!!")
>       render_action ''new''
>     end
>   end
>
> Thanks,
> Payam.
Duane Johnson
(canadaduane)




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Payam Fard

2005-Jun-21 21:35 UTC

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Re: Activerecord Many-to-many create question

Thanks again for your reply. Is this the change you
are proposing in your email? I have added
@assignment.save before getting the resources and
adding resources to the assinment. What happens is
that a record gets inserted into the assignment table,
but the corresponding entry into the join table does
not get inserted!!! I still do not get any error!

Did I follow your suggestion correctly?

     @assignment      Assignment.new(@params[:assignment])

    @assignment.save #Added based on your email

    resource = Resource.find(session[''resource_id''])
    @assignment.resources << resource
    logger.warn(@assignment)
    if @assignment.save!
      logger.warn("Inside if of assignment.save!!!")
      redirect_to :action => ''list''
    else
      logger.warn("Inside else of assignment.save!!!")
      render_action ''new''
    end
  end


--- Duane Johnson <duane.johnson-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> 
> On Jun 21, 2005, at 9:00 AM, Payam Fard wrote:
> 
> > Thanks for your reply. Here is how I have changed
> my
> > code, even though there is still no change to the
> > outcome of my program. @assignment.save! is not
> > throwing any exceptions or errors either. Here is
> the
> > modified version. Evertime I submit, I would go to
> the
> > else. I made a mistake in my original post, my
> join
> > table is called assignments_resources. When I
> print
> > the contents of assignment, I am getting the
> correct
> > values as well as the associated resource.
> >
> >   def create
> >     @assignment > Assignment.new(@params[:assignment])
> 
> Here''s the issue: you need to save your @assignment
> object before you  
> add the resource.  Otherwise, there is no
> @assignment.id that your  
> resource.assignment_id can be set to.  Perhaps you
> could re-arrange  
> your method, or else use Assignment.create instead. 
>  
> (Assignment.create would do the same thing as
> Assignment.new.save).
> 
> >     resource >
Resource.find(session[''resource_id''])
> >     @assignment.resources << resource
> >     logger.warn(@assignment)
> >     if @assignment.save!
> >       logger.warn("Inside if of
> assignment.save!!!")
> >       redirect_to :action => ''list''
> >     else
> >       logger.warn("Inside else of
> assignment.save!!!")
> >       render_action ''new''
> >     end
> >   end
> >
> > Thanks,
> > Payam.
> 
> Duane Johnson
> (canadaduane)
> 
> 
> > _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
> 


		
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Payam Fard

2005-Jun-22 12:47 UTC

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Re: Activerecord Many-to-many create question

Also on the same note, given I can get the following
solution working, I guess I have to run it as part of
a transaction so that either both records get inserted
or none, right?


--- Payam Fard <p_fard_2000-/E1597aS9LQAvxtiuMwx3w@public.gmane.org>
wrote:
> Thanks again for your reply. Is this the change you
> are proposing in your email? I have added
> @assignment.save before getting the resources and
> adding resources to the assinment. What happens is
> that a record gets inserted into the assignment
> table,
> but the corresponding entry into the join table does
> not get inserted!!! I still do not get any error!
> 
> Did I follow your suggestion correctly?
> 
>      @assignment >      Assignment.new(@params[:assignment])
> 
>     @assignment.save #Added based on your email
> 
>     resource = Resource.find(session[''resource_id''])
>     @assignment.resources << resource
>     logger.warn(@assignment)
>     if @assignment.save!
>       logger.warn("Inside if of assignment.save!!!")
>       redirect_to :action => ''list''
>     else
>       logger.warn("Inside else of
> assignment.save!!!")
>       render_action ''new''
>     end
>   end
> 
> 
> --- Duane Johnson
<duane.johnson-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> 
> > 
> > On Jun 21, 2005, at 9:00 AM, Payam Fard wrote:
> > 
> > > Thanks for your reply. Here is how I have
> changed
> > my
> > > code, even though there is still no change to
> the
> > > outcome of my program. @assignment.save! is not
> > > throwing any exceptions or errors either. Here
> is
> > the
> > > modified version. Evertime I submit, I would go
> to
> > the
> > > else. I made a mistake in my original post, my
> > join
> > > table is called assignments_resources. When I
> > print
> > > the contents of assignment, I am getting the
> > correct
> > > values as well as the associated resource.
> > >
> > >   def create
> > >     @assignment > > Assignment.new(@params[:assignment])
> > 
> > Here''s the issue: you need to save your
> @assignment
> > object before you  
> > add the resource.  Otherwise, there is no
> > @assignment.id that your  
> > resource.assignment_id can be set to.  Perhaps you
> > could re-arrange  
> > your method, or else use Assignment.create
> instead. 
> >  
> > (Assignment.create would do the same thing as
> > Assignment.new.save).
> > 
> > >     resource > >
Resource.find(session[''resource_id''])
> > >     @assignment.resources << resource
> > >     logger.warn(@assignment)
> > >     if @assignment.save!
> > >       logger.warn("Inside if of
> > assignment.save!!!")
> > >       redirect_to :action => ''list''
> > >     else
> > >       logger.warn("Inside else of
> > assignment.save!!!")
> > >       render_action ''new''
> > >     end
> > >   end
> > >
> > > Thanks,
> > > Payam.
> > 
> > Duane Johnson
> > (canadaduane)
> > 
> > 
> > > _______________________________________________
> > Rails mailing list
> > Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> >
> http://lists.rubyonrails.org/mailman/listinfo/rails
> > 
> 
> 
> 
> 		
> ____________________________________________________
> 
> Yahoo! Sports 
> Rekindle the Rivalries. Sign up for Fantasy Football
> 
> http://football.fantasysports.yahoo.com
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
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Rails - Jun 2005 - Activerecord Many-to-many create question

Activerecord Many-to-many create question

Re: Activerecord Many-to-many create question

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How to write insertion sql to the logs

Re: Activerecord Many-to-many create question

Re: Activerecord Many-to-many create question

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