Scenario:
Table in database has two fields, id and category (table name is:
categories)
Controller is named category_controller.rb
Model is named category.rb
Helper is named category_helper.rb
Form is named list.rhtml in view\category directory
The code in play on the form is (from generating scaffold):
<% for category in @categories %>
<tr>
<td><%= h(category.category) %>
<td><%= link_to ''Show'', :action =>
''show'', :id => category %></td>
<td><%= link_to ''Edit'', :action =>
''edit'', :id => category %></td>
<td><%= link_to ''Delete'', { :action =>
''destroy'', :id => category },
:confirm => ''Are you sure?'', :post => true
%></td>
</tr>
<% end %>
link_to on form is to action destroy
code that was in action in category_controller (on first attempt that
did not work):
cat = params[:category]
Problem is: cat was nil
Now I worked around it by doing this:
@category = Category.find(params[:id])
cat = @category.category
So, why if I can get the value of params[:id] from the form cannot I not
also get the value of param[:category]?
Is it possible I am getting a name clash here? And if not a name clash,
then of course the question becomes what might it be?
There doesn''t seem to be any confusion in the form with this line:
<td><%= h(category.category) %>
But then the context seems such that there wouldn''t be, but perhaps the
context is not so clear in the action in the controller?
--
Posted via http://www.ruby-forum.com/.
Hi Scott, The reason the category is not available is that you are not passing it in your link_to. To pass it just add a :category => category.category to your link_to params. This line: <td><%= h(category.category) %> will only display the category, but will not send it up when someone clicks on the links. Tom On 7/7/06, Scott Helfrich <r-scott-h@sbcglobal.net> wrote:> Scenario: > > Table in database has two fields, id and category (table name is: > categories) > Controller is named category_controller.rb > Model is named category.rb > Helper is named category_helper.rb > Form is named list.rhtml in view\category directory > > The code in play on the form is (from generating scaffold): > > <% for category in @categories %> > <tr> > <td><%= h(category.category) %> > <td><%= link_to ''Show'', :action => ''show'', :id => category %></td> > <td><%= link_to ''Edit'', :action => ''edit'', :id => category %></td> > <td><%= link_to ''Delete'', { :action => ''destroy'', :id => category }, > :confirm => ''Are you sure?'', :post => true %></td> > </tr> > <% end %> > > link_to on form is to action destroy > > code that was in action in category_controller (on first attempt that > did not work): > > cat = params[:category] > > Problem is: cat was nil > > Now I worked around it by doing this: > > @category = Category.find(params[:id]) > cat = @category.category > > So, why if I can get the value of params[:id] from the form cannot I not > also get the value of param[:category]? > > Is it possible I am getting a name clash here? And if not a name clash, > then of course the question becomes what might it be? > > There doesn''t seem to be any confusion in the form with this line: > <td><%= h(category.category) %> > But then the context seems such that there wouldn''t be, but perhaps the > context is not so clear in the action in the controller? > > -- > Posted via http://www.ruby-forum.com/. > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails >-- Tom Davies http://atomgiant.com http://gifthat.com
On Jul 7, 2006, at 6:48 AM, Scott Helfrich wrote:> <snip/>> The code in play on the form is (from generating scaffold): > > <% for category in @categories %> > <tr> > <td><%= h(category.category) %> > <td><%= link_to ''Show'', :action => ''show'', :id => category %></td> > <td><%= link_to ''Edit'', :action => ''edit'', :id => category %></td> > <td><%= link_to ''Delete'', { :action => ''destroy'', :id => > category }, > :confirm => ''Are you sure?'', :post => true %></td> > </tr> > <% end %> > > link_to on form is to action destroy > > code that was in action in category_controller (on first attempt that > did not work): > > cat = params[:category] > > Problem is: cat was nilwhen you have a construct like ":id => category", the value given to the params[:id] is obtained from category.to_param which is usuallly the same as category.id, that is, the primary key for the model. This particular bit of magic was clarified by Dave Thomas in response to my question last fall at a No Fluff Just Stuff conference (yeah, Java-centric, but a surprising amount of Ruby and Rails thrown in there). -Rob
Thanks Tom and Rob. Appreciate the response. I follow what you are both saying and I understand. I''m glad there is no name clash here as I have run into that previously, but that was too obvious - the table was named request! (I was just getting started.) Anyway, I''m still somewhat confused as I could have swore I read in one of my books that all the field values on the form are returned and available to the controller, automatically done for you and each field then available to you through params[:some_name]. Did I misunderstand or read it wrong? This would be similar to a form bean, though it did take a call to make it happen, whereas I thought it was automatic in Rails. If I understood that correctly, then is it different for this scenario because it is a list? (Of course I am trying to locate where I got the idea from but so far have not been able to find it in the book. Now, I am using partials with a layout template, and it just occurred to me that I do not have a start_form_tag(:action => ...") in my partial form. I hope this is making sense as I''m trying to deal here with a concept I thought existed but cannot find it at the moment. -- Posted via http://www.ruby-forum.com/.
Hi Scott, Scott Helfrich wrote:> Anyway, I''m still somewhat confused as I could > have swore I read in one of my books that all the > field values on the form are returned and available > to the controller, automatically done for you and > each field then available to you through > params[:some_name]. Did I misunderstand or > read it wrong?Two related items seem to me to be at the root of your current problem, one of which you''ve already figured out. Forms are not pages, they''re ''containers'' (that are part of a page) that start and end with explicit tags. The second item is about ''fields''. Your understanding above is correct. I think the problem you''re having here is your understanding of the term ''field''. Your view contained no fields in the form-sense of the word. A form field is an object like a text_field, a check_box, a radio_button, etc. The user-entered values of those things will be passed back to the controller in the params hash when the form is submitted. hth, Bill
Bill Walton wrote:> Hi Scott, > > Scott Helfrich wrote: > >> Anyway, I''m still somewhat confused as I could >> have swore I read in one of my books that all the >> field values on the form are returned and available >> to the controller, automatically done for you and >> each field then available to you through >> params[:some_name]. Did I misunderstand or >> read it wrong? > > Two related items seem to me to be at the root of your current problem, > one > of which you''ve already figured out. Forms are not pages, they''re > ''containers'' (that are part of a page) that start and end with explicit > tags. The second item is about ''fields''. Your understanding above is > correct. I think the problem you''re having here is your understanding > of > the term ''field''. Your view contained no fields in the form-sense of > the > word. A form field is an object like a text_field, a check_box, a > radio_button, etc. The user-entered values of those things will be > passed > back to the controller in the params hash when the form is submitted. > > hth, > BillThanks Bill. I get it now. I was confused and that cleared it up. I just took a look now at my ''new'' view and it does use the start_form_tag. Makes perfect sense and ties back in to what Tom and Rob said and I''ve got the big picture now with all three pieces. Thanks guys. I needed all three pieces to understand this. Much appreciated. -- Posted via http://www.ruby-forum.com/.
Hi Scott: Scott Helfrich wrote:> Thanks Bill. I get it now. I was confused and that cleared it up.Glad to help!> I just took a look now at my ''new'' view and it does use the > start_form_tag.Don''t forget the end_form_tag. ;-)> Thanks guys. I needed all three pieces to understand this. > Much appreciated.I''m sure I can safely speak for Tom and Rob too when I say... welcome aboard! Best regards, Bill
Yes, welcome aboard Scott :) I think you will find that this list is very helpful in getting you running with Ruby On Rails. Good luck, Tom On 7/7/06, Bill Walton <bill.walton@charter.net> wrote:> Hi Scott: > > Scott Helfrich wrote: > > Thanks Bill. I get it now. I was confused and that cleared it up. > > Glad to help! > > > I just took a look now at my ''new'' view and it does use the > > start_form_tag. > > Don''t forget the end_form_tag. ;-) > > > Thanks guys. I needed all three pieces to understand this. > > Much appreciated. > > I''m sure I can safely speak for Tom and Rob too when I say... welcome > aboard! > > Best regards, > Bill > > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails >-- Tom Davies http://atomgiant.com http://gifthat.com
Very much appreciate the welcome Bill and Tom; really do. It will take some time, but I am hoping to be able to contribute with being of help to others eventually as this is I think the greatest form of saying thank you. But it will be a while. In the mean time, for this out of work COBOLer/some Java, it means a lot to me to be able to get some help like this. And so I will try to make my questions good, well documented and understandable so that the question and the answers will be of benefit to others as well as myself. So again, sincerely, thank you for the help and the welcome. :) It''s good to be part of the RoR community. -- Posted via http://www.ruby-forum.com/.