I have these tables set up like this: listings has_many :states <field>state_id [int] <other fields.... .............. .............> states belongs_to: listings <field>name <other fields.. ............... .................> In my view I have <%= listing.name %> have also tried listing.state_id.name , that didn''t seem to do the magic either. This is the error message: NoMethodError in Company#list Showing *app/views/company/list.rhtml* where line *#29* raised: undefined method `name'' for 7:Fixnum basically the action code is: find(:all) What am I doing wrong ? TIA Stuart -------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060714/090358b4/attachment.html
The state_id field goes always inside the model that belongs_to the state model. At first glance it doesn''t make much sense for states to belong_to listings, so I suspect that what you want is to reverse the association, leaving the state_id field where it is. - foobario On 7/14/06, Dark Ambient <sambient@gmail.com> wrote:> > I have these tables set up like this: > > > listings has_many :states > <field>state_id [int] > <other fields.... > .............. > .............> > > states belongs_to: listings > <field>name > <other fields.. > ............... > .................> > > In my view I have <%= listing.name %> > have also tried listing.state_id.name , that didn''t seem to do the magic > either. > > This is the error message: > NoMethodError in Company#list > > Showing *app/views/company/list.rhtml* where line *#29* raised: > > undefined method `name'' for 7:Fixnum > > > > basically the action code is: find(:all) > What am I doing wrong ? > > TIA > Stuart > > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails > > >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060714/1caf2d59/attachment.html
You have your foreign key the wrong way round if listings have many states. The ''states'' table should have a ''listing_id''. Then you can access a listing''s states like this: listing.states That''ll give you a collection of states: <% listing.states.each do |state| %> <%= state.name %><br/> <% end %> That will print the name of each state related to the listing. To access the listing via the state, you just do: state.listing So you''d access an attribute of listing like this: <%= state.listing.whatever %> Hope that helps! Steve
No sorry that isn''t the goal , apologies for bad explanation , I''ll try better now. table listings: has a field called state_id (this is where a number would go that corresponds to the id in the states table. states table is like this (id, name) 1 Alaska 2 Alabama listings table would have an entry in the state_id field i.e. 2 so the view for the listings table should display Alabama Stuart On 7/14/06, Stephen Bartholomew <sb@2404.co.uk> wrote:> > You have your foreign key the wrong way round if listings have many > states. The ''states'' table should have a ''listing_id''. > > Then you can access a listing''s states like this: > > listing.states > > That''ll give you a collection of states: > > <% listing.states.each do |state| %> > <%= state.name %><br/> > <% end %> > > That will print the name of each state related to the listing. > > To access the listing via the state, you just do: > > state.listing > > So you''d access an attribute of listing like this: > > <%= state.listing.whatever %> > > Hope that helps! > > Steve > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060714/47e9e54c/attachment.html
Ok - So a listing belongs_to a state. <%= listing.state.name %> should work. That''s assuming: listings -------- id state_id states ------- id name class Listing < ActiveRecord::Base belongs_to :state end class State < ActiveRecord::Base has_many :listings end Steve
Dark Ambient wrote on 14.07.2006 21:01:> I have these tables set up like this: > > > listings has_many :states > <field>state_id [int] > <other fields.... > .............. > .............> > > states belongs_to: listings > <field>name > <other fields.. > ............... > .................> > > In my view I have <%= listing.name %> > have also tried listing.state_id.name , that didn''t seem to do the magic > either. > > This is the error message: > NoMethodError in Company#list > > Showing *app/views/company/list.rhtml* where line *#29* raised: > > undefined method `name'' for 7:FixnumYou should read more documentation... http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html I think your associations are wrong or you table descriptions misses something. I see only state_id in listings table. So your Listing has a belongs_to :state and your State has_one :listing No more associations available. To access variables from an action in the view, the vars must be instance variables. So there should be <%= @listing.state.name %> Markus
On 7/14/06, Stephen Bartholomew <sb@2404.co.uk> wrote:> > class Listing < ActiveRecord::Base > belongs_to :state > end > > > class State < ActiveRecord::Base > has_many :listings > end > > SteveTo me this looks wrong. It didn''t work either so not sure what''s going on. It looks though as it would be reverse. listings could have many states, Stuart -------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060714/ef3e1242/attachment-0001.html
If listings can have many states, and (I''m assuming) states can have many listings, it sounds like you need a has_and_belongs_to_many association. - foobario On 7/14/06, Dark Ambient <sambient@gmail.com> wrote:> > > > On 7/14/06, Stephen Bartholomew <sb@2404.co.uk> wrote: > > > class Listing < ActiveRecord::Base > > belongs_to :state > > end > > > > > > class State < ActiveRecord::Base > > has_many :listings > > end > > > > Steve > > > To me this looks wrong. It didn''t work either so not sure what''s going > on. > It looks though as it would be reverse. listings could have many states, > > Stuart > > > > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails > > >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060714/ced0e535/attachment.html
Bear with me a moment, because my database skills are not the greatest. So I''m thinking this through out loud: 1 listing can only have one state associated with it. The listings tables can have many states within it. The states table wouldn''t have multiple entries for a state. That make sense ? On 7/14/06, foobario <mkrails@gmail.com> wrote:> > If listings can have many states, and (I''m assuming) states can have many > listings, it sounds like you need a has_and_belongs_to_many association. > > - foobario > > > > On 7/14/06, Dark Ambient <sambient@gmail.com> wrote: > > > > > On 7/14/06, Stephen Bartholomew < sb@2404.co.uk> wrote: > > > class Listing < ActiveRecord::Base > > belongs_to :state > > end > > > > > > class State < ActiveRecord::Base > > has_many :listings > > end > > > > Steve > > > To me this looks wrong. It didn''t work either so not sure what''s going > on. > It looks though as it would be reverse. listings could have many states, > > Stuart > > > > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails > > > > > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails > > >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060714/2841111a/attachment.html
Based on what you just said:>The states table wouldn''t have multiple entries for a state.So your states can''t belong_to something else (doing so would tie up that state entry).>1 listing can only have one state associated with it.A listing only associates to one state. We already know that the state can''t belong_to the listing, so it looks like the listing belongs_to State.>The listings tables can have many states within it....which is another way of saying that State has_many :listings. I know from recent personal experience that my first-order guess at how a DB should be formed was often exactly backwards. And it gets confusing thinking about whether an association applies to the whole table or to an entry in that table. It does get easier with time. - foobario -------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060714/8b84853e/attachment-0001.html
On 7/14/06, foobario <mkrails@gmail.com> wrote:> > Based on what you just said: > > >The states table wouldn''t have multiple entries for a state. > > So your states can''t belong_to something else (doing so would tie up that > state entry). > > > >1 listing can only have one state associated with it. > > A listing only associates to one state. We already know that the state > can''t belong_to the listing, so it looks like the listing belongs_to State. > > > >The listings tables can have many states within it. > > ...which is another way of saying that State has_many :listings. >I went back and checked teh r4rmusic1 site form Ruby on Rails to see how my tables would fit. I''m saying this because it can be confusing to say listings table can have many states. I believe though the relationships are not set on the table, but on the objects within the table, so a listing can only have one state. Stuart I know from recent personal experience that my first-order guess at how a DB> should be formed was often exactly backwards. And it gets confusing > thinking about whether an association applies to the whole table or to an > entry in that table. It does get easier with time. > > > - foobario > > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails > > >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060714/590addc1/attachment.html
> To me this looks wrong. It didn''t work either so not sure what''s going on. > It looks though as it would be reverse. listings could have many states,If a listing belongs to a state, this is known as a one-to-many relationship. i.e. One state can have many listings. This is represented in Rails using the code examples i gave earlier (belongs_to/has_many). If listings can have many states and states can have many listings, then you need to use: has_and_belongs_to_many. Steve
On 7/14/06, Stephen Bartholomew <sb@2404.co.uk> wrote:> > > To me this looks wrong. It didn''t work either so not sure what''s going > on. > > It looks though as it would be reverse. listings could have many states, > If a listing belongs to a state, this is known as a one-to-many > relationship. i.e. One state can have many listings. This is > represented in Rails using the code examples i gave earlier > (belongs_to/has_many). > > If listings can have many states and states can have many listings, then > you need to use: has_and_belongs_to_many.This statement is confusing me. one listing (in the listings table) can only have one state. Is that how I define the relationship or is it based on the entire table ? Stuart Steve> > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060714/fcc0072d/attachment-0001.html
> This statement is confusing me. one listing (in the listings table) > can only have one state. Is that how I define the relationship or is > it based on the entire table ?I think you might be getting confused about what the relationship refers to. Don''t think about the table as whole - just think about the model. You are representing a Listing. A listing can be linked to one state. One state can be linked to many listings. For example, you could have 5 listings in California. In rails we say that a listing ''belongs_to'' a state and a state ''has_many'' listings. The issue you''re having is with database design concepts. Once you understand them, it''ll all make sense. Hope this helps! Steve
Well I''m getting no where fast.
I do understand what your saying, so here is my code,maybe something else is
wrong.
listing model:
class Listing < ActiveRecord::Base
belongs_to :state
def self.current_openings
find(:all)
end
end
state model:
class State < ActiveRecord::Base
has_many :listing
end
Then in the view:
<% for listing in @listings -%>
<%= listing.category_id %></td>
............
............
<%= listing.state.name %>
<% end %>
Then the actual database:
------------------------
listings (table):
id primary id
......
state
-----------------
states (table)
id primary id
name
--------------
On 7/14/06, Stephen Bartholomew <sb@2404.co.uk>
wrote:>
> > This statement is confusing me. one listing (in the listings table)
> > can only have one state. Is that how I define the relationship or is
> > it based on the entire table ?
> I think you might be getting confused about what the relationship refers
> to. Don''t think about the table as whole - just think about the
model.
> You are representing a Listing. A listing can be linked to one state.
> One state can be linked to many listings.
>
> For example, you could have 5 listings in California. In rails we say
> that a listing ''belongs_to'' a state and a state
''has_many'' listings.
>
> The issue you''re having is with database design concepts. Once
you
> understand them, it''ll all make sense.
>
> Hope this helps!
>
> Steve
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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> Then the actual database:> ------------------------ > listings (table): > id primary id > ...... > state > ----------------- > states (table) > id primary id > name You need to have a state_id in the listings table. That should have the id of the state that the listing belongs to in it. Looks like your relationships are set up ok and providing you have a listing linked to a particular state, you should be able to do: <%= listing.state.name %> If that still isn''t working, please post any errors you''re getting. If you''re not getting any errors, check the database and make sure the actual data is correct; i.e. a listing as a state_id set. Steve
On 7/14/06, Stephen Bartholomew <sb@2404.co.uk> wrote:> > Then the actual database: > > ------------------------ > > listings (table): > > id primary id > > ...... > > state > > ----------------- > > states (table) > > id primary id > > name > > You need to have a state_id in the listings table. That should have the > id of the state that the listing belongs to in it. > > Looks like your relationships are set up ok and providing you have a > listing linked to a particular state, you should be able to do: > > <%= listing.state.name %> > > If that still isn''t working, please post any errors you''re getting. If > you''re not getting any errors, check the database and make sure the > actual data is correct; i.e. a listing as a state_id set. > > SteveSince you said I need to have a state_id in the listings table I changed state to state_id. then I think the view code would be: <%= listing.state_id.name %> and get this error: undefined method `name'' for 7:Fixnum if I leave it as <%= listing.state.name %> then the error is: undefined method `state'' for #<Position:0x33b6888> Stuart
Okay , it''s finally working. In the listing model I had "belongs_to :states" it needed to be "belongs_to :state" So when creating these relationships I need to use the class name, lower case ? / singular form ? Stuart On 7/14/06, Dark Ambient <sambient@gmail.com> wrote:> On 7/14/06, Stephen Bartholomew <sb@2404.co.uk> wrote: > > > Then the actual database: > > > ------------------------ > > > listings (table): > > > id primary id > > > ...... > > > state > > > ----------------- > > > states (table) > > > id primary id > > > name > > > > You need to have a state_id in the listings table. That should have the > > id of the state that the listing belongs to in it. > > > > Looks like your relationships are set up ok and providing you have a > > listing linked to a particular state, you should be able to do: > > > > <%= listing.state.name %> > > > > If that still isn''t working, please post any errors you''re getting. If > > you''re not getting any errors, check the database and make sure the > > actual data is correct; i.e. a listing as a state_id set. > > > > Steve > > Since you said I need to have a state_id in the listings table I > changed state to state_id. > then I think the view code would be: <%= listing.state_id.name %> > and get this error: > undefined method `name'' for 7:Fixnum > > if I leave it as <%= listing.state.name %> > then the error is: > undefined method `state'' for #<Position:0x33b6888> > > Stuart >
stuart fellowes wrote:> Okay , it''s finally working. > In the listing model I had "belongs_to :states" > it needed to be "belongs_to :state" > So when creating these relationships I need to use the class name, > lower case ? / singular form ? > > StuartHi, Wen using a relationship statement that implies plurality, e.g. has_many or has_and_belongs_to many, you use the plural, and when using one that implies singularity, e.g. has_one or belongs_to, you use the singular. Hope that helps Chris -- Posted via http://www.ruby-forum.com/.
> So when creating these relationships I need to use the class name, > lower case ? / singular form ?Rails relationships are specified like english. For example, when talking about the listings/states relationship you would say: A listing belongs to a state and A state has many listings Therefore in rails you define the relationship as follows: class Listing < ActiveRecord::Base belongs_to :state end class State < ActiveRecord::Base has_many :states end So just think about how you would *say* the relationship and it should work. Steve
k...I appreciate all the help on this and it will be useful. They''ll be about a dozen relationships with the listings tables , so it should be good practice for me :) Stuart On 7/15/06, Stephen Bartholomew <sb@2404.co.uk> wrote:> > So when creating these relationships I need to use the class name, > > lower case ? / singular form ? > Rails relationships are specified like english. For example, when > talking about the listings/states relationship you would say: > > A listing belongs to a state > and > A state has many listings > > Therefore in rails you define the relationship as follows: > > class Listing < ActiveRecord::Base > belongs_to :state > end > > class State < ActiveRecord::Base > has_many :states > end > > So just think about how you would *say* the relationship and it should work. > > Steve > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails >