Hey all,
I''ve been working with rails for a grand total of 8 hours, and have run
up against the first problem I haven''t been able to adequately solve
using google.
So I''ve got a schema that basically consists of a bunch of researchers.
Each researcher has only one notebook. I''m trying to ensure that only
one notebook can be created for each user. Below is the code I''ve been
using in the create method for my notebook:
existingbook = Notebook.find(:first, params[:researcher_id])
@notebook = Notebook.new(params[:notebook])
respond_to do |format|
if (existingbook.nil?)
if @notebook.save
flash[:notice] = ''Notebook was successfully
created.''
format.html { redirect_to(@notebook) }
format.xml { render :xml => @notebook, :status => :created,
:location => @notebook }
else
format.html { render :action => "new" }
format.xml { render :xml => @notebook.errors, :status =>
:unprocessable_entity }
end
else
flash[:error] = ''A notebook already exists for this
user''
format.html { render :action => "new" }
format.xml { render :xml => @notebook.errors, :status =>
:unprocessable_entity }
end
end
The basic idea is to check the notebook table for the researcher id
specified by the user. If a notebook already exists, send an error
message back. Otherwise, create the notebook as usual. However, the
above code doesn''t work like I think it should. Basically what I have
above always allows another notebook to be created (e.g. I can enter
researcher_id of 1 five times in a row without an error). Is there
something I''m missing? Is there any way to check the database to see if
a value exists already before saving it off? I''m probably missing
something simple here, and if anyone has some input I would greatly
appreciate the assistance.
--
Posted via http://www.ruby-forum.com/.
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On 13 Feb 2009, at 18:22, Matt Billock wrote:> > Hey all, > > I''ve been working with rails for a grand total of 8 hours, and have > run > up against the first problem I haven''t been able to adequately solve > using google. > > So I''ve got a schema that basically consists of a bunch of > researchers. > Each researcher has only one notebook. I''m trying to ensure that only > one notebook can be created for each user. Below is the code I''ve been > using in the create method for my notebook: > > existingbook = Notebook.find(:first, params[:researcher_id])This doesn''t find a notebook with the specified researcher_id. It just finds a notebook (and thinking about it, how could Notebook.find know that the parameter you were giving it was a researched_id and not something else?_ If you check log/development.log while you''re doing this you can see the sql queries generated which would reveal this. What you probably meant to write is Notebook.find_by_researcher_id(params[:researcher_id]) or if you wanted to be long winded Notebook.find :first, :conditions => ["researcher_id = ?", params[:researcher_id]] Lastly, take a look at validates_uniqueness_of and be aware of the race condition inherent in the way it works (your code suffers from the same problem) Fred> > @notebook = Notebook.new(params[:notebook]) > > respond_to do |format| > if (existingbook.nil?) > if @notebook.save > flash[:notice] = ''Notebook was successfully created.'' > format.html { redirect_to(@notebook) } > format.xml { render :xml => @notebook, :status => :created, > :location => @notebook } > else > format.html { render :action => "new" } > format.xml { render :xml => @notebook.errors, :status => > :unprocessable_entity } > end > else > flash[:error] = ''A notebook already exists for this user'' > format.html { render :action => "new" } > format.xml { render :xml => @notebook.errors, :status => > :unprocessable_entity } > end > end > > The basic idea is to check the notebook table for the researcher id > specified by the user. If a notebook already exists, send an error > message back. Otherwise, create the notebook as usual. However, the > above code doesn''t work like I think it should. Basically what I have > above always allows another notebook to be created (e.g. I can enter > researcher_id of 1 five times in a row without an error). Is there > something I''m missing? Is there any way to check the database to see > if > a value exists already before saving it off? I''m probably missing > something simple here, and if anyone has some input I would greatly > appreciate the assistance. > -- > Posted via http://www.ruby-forum.com/. > > >--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Frederick Cheung wrote:> On 13 Feb 2009, at 18:22, Matt Billock wrote: > > This doesn''t find a notebook with the specified researcher_id. It just > finds a notebook (and thinking about it, how could Notebook.find know > that the parameter you were giving it was a researched_id and not > something else?_ > > If you check log/development.log while you''re doing this you can see > the sql queries generated which would reveal this. > > What you probably meant to write is > Notebook.find_by_researcher_id(params[:researcher_id]) or if you > wanted to be long winded > > Notebook.find :first, :conditions => ["researcher_id = ?", > params[:researcher_id]] > > Lastly, take a look at validates_uniqueness_of and be aware of the > race condition inherent in the way it works (your code suffers from > the same problem) > > FredThanks much for the reply! I figured it was something simple like that. I just implemented the validates_uniqueness_of attribute before coming back here and it does the job much better than I could :) -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Hey man. Welcome! First thing, from hereonin, please put more meaningful subject names. We get lots of noob questions. Second, what you''d like is belongs_to association. Take a look in activerecord::base documentation at api.rubyonrails.org Blog: http://random8.zenunit.com/ Learn rails: http://sensei.zenunit.com/ On 14/02/2009, at 5:22 AM, Matt Billock <rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org > wrote:> > Hey all, > > I''ve been working with rails for a grand total of 8 hours, and have > run > up against the first problem I haven''t been able to adequately solve > using google. > > So I''ve got a schema that basically consists of a bunch of > researchers. > Each researcher has only one notebook. I''m trying to ensure that only > one notebook can be created for each user. Below is the code I''ve been > using in the create method for my notebook: > > existingbook = Notebook.find(:first, params[:researcher_id]) > @notebook = Notebook.new(params[:notebook]) > > respond_to do |format| > if (existingbook.nil?) > if @notebook.save > flash[:notice] = ''Notebook was successfully created.'' > format.html { redirect_to(@notebook) } > format.xml { render :xml => @notebook, :status => :created, > :location => @notebook } > else > format.html { render :action => "new" } > format.xml { render :xml => @notebook.errors, :status => > :unprocessable_entity } > end > else > flash[:error] = ''A notebook already exists for this user'' > format.html { render :action => "new" } > format.xml { render :xml => @notebook.errors, :status => > :unprocessable_entity } > end > end > > The basic idea is to check the notebook table for the researcher id > specified by the user. If a notebook already exists, send an error > message back. Otherwise, create the notebook as usual. However, the > above code doesn''t work like I think it should. Basically what I have > above always allows another notebook to be created (e.g. I can enter > researcher_id of 1 five times in a row without an error). Is there > something I''m missing? Is there any way to check the database to see > if > a value exists already before saving it off? I''m probably missing > something simple here, and if anyone has some input I would greatly > appreciate the assistance. > -- > Posted via http://www.ruby-forum.com/. > > >--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Create a unique index for the foreign key (user_id) in the notebook table! --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---