Rails - Mar 2008 - Newbie worries with "Developing Rails Applications on Max OSX Leopard"

Hello There,
As a new comer to RoR, I started to follow the article
http://developer.apple.com/tools/developonrailsleopard.html. In short
you create to entities and one one-to-many relation linking them.

Everything was good until the establishment of the relation. I am
unable to go any further than "Linking Models Together" : I can create
the "vendors" mentionned in the exemple, and I can get an
"event" to
look to. But when I try to create an "expense", I get a message
saying :
>> event.expenses.create(:vendor => vendor1, :amount => 75.00)
NoMethodError: undefined method `expenses'' for #<Event:0x125e008>
	from /Library/Ruby/Gems/1.8/gems/activerecord-2.0.2/lib/active_record/
attribute_methods.rb:205:in `method_missing''
	from (irb):2

Could anybody help me ? I have checked the classes files, everything
seems according to the article. I did checks on the database, the
table "expenses" has been created but is empty. The "id"
fiels are
present in each of the tables... I don''t see where to look to now.

Thanks in advance,

Thierry


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Thierry wrote:
>>> event.expenses.create(:vendor => vendor1, :amount => 75.00)
> NoMethodError: undefined method `expenses'' for
#<Event:0x125e008>
>   from /Library/Ruby/Gems/1.8/gems/activerecord-2.0.2/lib/active_record/
> attribute_methods.rb:205:in `method_missing''
>   from (irb):2
> 
> Could anybody help me ? I have checked the classes files, everything
> seems according to the article. I did checks on the database, the
> table "expenses" has been created but is empty. The
"id" fiels are
> present in each of the tables... I don''t see where to look to now.
Do you have the following in your Event class:

has_many :expenses

?
This is the line that give the Event class the method "expenses" which
links to the Expense class.  And in the Expense class:

belongs_to :event

to get the map the other way around giving the Expense class the method 
"event".

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> 
> Thierry
To easily remember what Mark told you, just remember that the foreign 
key is always in the model that has the belongs_to relationship..  When 
I first started playing with AR, that little fact made everything much 
more easier to comprehend..

hth

ilan


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Mark,

Thanks for your answer. Precisely, it seems to me that I have
everything right. I put the code here :

===== > In the "event.rb" file :

class Event < ActiveRecord::Base
	validates_presence_of :name
	validates_numericality_of :budget, :greater_than => 0.0

	has_many :expenses
	has_many :vendors, :through => :expenses

	def total_expenses
		expenses.sum(:amount) || BigDecimal("0.0")
	end

	def budget_exceeded?
		total_expenses > budget
	end

end

===> In the expense.rb file :

class Expense < ActiveRecord::Base
  belongs_to :event
  belongs_to :vendor
end

===> In the vendor.rb file :

class Vendor < ActiveRecord::Base
  has_many :expenses
  has_many :events, :through => :expenses
end

Thanks again


On 8 mar, 16:03, Mark Bush
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> Thierry wrote:
> >>> event.expenses.create(:vendor => vendor1, :amount =>
75.00)
> > NoMethodError: undefined method `expenses'' for
#<Event:0x125e008>
> >   from
/Library/Ruby/Gems/1.8/gems/activerecord-2.0.2/lib/active_record/
> > attribute_methods.rb:205:in `method_missing''
> >   from (irb):2
>
> > Could anybody help me ? I have checked the classes files, everything
> > seems according to the article. I did checks on the database, the
> > table "expenses" has been created but is empty. The
"id" fiels are
> > present in each of the tables... I don''t see where to look to
now.
>
> Do you have the following in your Event class:
>
> has_many :expenses
>
> ?
> This is the line that give the Event class the method "expenses"
which
> links to the Expense class.  And in the Expense class:
>
> belongs_to :event
>
> to get the map the other way around giving the Expense class the method
> "event".
>
> --
> Posted viahttp://www.ruby-forum.com/.
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Thierry wrote:
> Thanks for your answer. Precisely, it seems to me that I have
> everything right. I put the code here :
That looks fine.  Can you post the results of running (in the 
application console):

Event.column_names

and:

Expense.column_names

Just to confirm that these two models are both set up correctly too...

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That''s it :
>> Expense.column_names
=> ["id", "event_id", "vendor_id",
"amount", "created_at",
"updated_at"]
>> Event.column_names
=> ["id", "name", "budget",
"created_at", "updated_at"]
>> Expense.column_names
=> ["id", "event_id", "vendor_id",
"amount", "created_at",
"updated_at"]
>> Vendor.column_names
=> ["id", "name", "email",
"created_at", "updated_at"]
>>
 It looks fine too, doesn''t it ?

On 8 mar, 16:44, Mark Bush
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> Thierry wrote:
> > Thanks for your answer. Precisely, it seems to me that I have
> > everything right. I put the code here :
>
> That looks fine.  Can you post the results of running (in the
> application console):
>
> Event.column_names
>
> and:
>
> Expense.column_names
>
> Just to confirm that these two models are both set up correctly too...
>
> --
> Posted viahttp://www.ruby-forum.com/.
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Thierry wrote:
> That''s it :
> 
>>> Expense.column_names
> => ["id", "event_id", "vendor_id",
"amount", "created_at",
> "updated_at"]
>>> Event.column_names
> => ["id", "name", "budget",
"created_at", "updated_at"]
>  It looks fine too, doesn''t it ?
Yes. Was the error produced in a console that you started *after* making 
the extra changes to the Event and Expense models?  In a console, the 
models are loaded when first used only and if you change them then you 
need to reload them.  You can do this with:

reload!

or just by restarting the console (use "quit" to exit, then run the 
console again).

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I did it as follows :

$ script/console
Loading development environment (Rails 2.0.2)
>> event = Event.find_by_name(''Bienvenue'')
=> #<Event id: 4, name: "Bienvenue", budget: #<BigDecimal:
125d57c,''0.456E3'',4(8)>, created_at: "2008-03-05
17:33:11",
updated_at: "2008-03-05 17:33:11">
>> event.expenses.create(:vendor => vendor1, :amount => 75.00)
NoMethodError: undefined method `expenses'' for #<Event:0x125dd88>
	from /Library/Ruby/Gems/1.8/gems/activerecord-2.0.2/lib/active_record/
attribute_methods.rb:205:in `method_missing''
	from (irb):2
>>
I am really lost...
>
> reload!
>
> or just by restarting the console (use "quit" to exit, then run
the
> console again).
>
> --
> Posted viahttp://www.ruby-forum.com/.
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SOLVED

In fact, I have been fooled by XCode that does not save the files when
it tells you that it does... I had to close completely XCode for some
modifications to be taken into account by rails. I have noticed this
when I had to restart my computer (battery low), my files where in an
old version. When I retyped the missing code I made typos, and I saw
them appear in the logs. The only solution to correct them has been to
close completely XCode and to execute a reload! in the console... A
bit strange.
Thanks to all and sorry for your time,

Thierry


On 8 mar, 17:31, Thierry
<Thierry.Jeanne...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> I did it as follows :
>
> $ script/console
> Loading development environment (Rails 2.0.2)>> event =
Event.find_by_name(''Bienvenue'')
>
> => #<Event id: 4, name: "Bienvenue", budget:
#<BigDecimal:
> 125d57c,''0.456E3'',4(8)>, created_at: "2008-03-05
17:33:11",
> updated_at: "2008-03-05 17:33:11">>>
event.expenses.create(:vendor => vendor1, :amount => 75.00)
>
> NoMethodError: undefined method `expenses'' for
#<Event:0x125dd88>
>         from
/Library/Ruby/Gems/1.8/gems/activerecord-2.0.2/lib/active_record/
> attribute_methods.rb:205:in `method_missing''
>         from (irb):2
>
>
>
> I am really lost...
>
>
>
> > reload!
>
> > or just by restarting the console (use "quit" to exit, then
run the
> > console again).
>
> > --
> > Posted viahttp://www.ruby-forum.com/.
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I had this exact same problem.  Found this page searching for a
solution to my "NoMethodError" blues.  Had to close XCode and re-open
it for the changes to be recognized.  That is a VERY annoying
problem.

Also had to quit the ruby console and restart it.  Using the "reload!"
command mentioned above did not work.
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