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Gijs Nijholt

2006-May-24 13:46 UTC

[Rails] AR foreign key problem.

Hello Railslist,

(I''m using RadRails 0.6.3 on Windows XP with Ruby 1.8.4, Rails 1.1 and
SQLite3)

I have two tables in the database: "locations" and
"customers":

customers.sql
---
id INT PRIMARY KEY
name VARCHAR 255
address VARCHAR 255
postal_code VARCHAR 255
city VARCHAR 255
---

locations.sql
---
id INT PRIMARY KEY
postal_code TEXT
longitude FLOAT
latitude FLOAT
---


I''ve created two models (customer.rb and location.rb):

customer.rb
---
class Customer < ActiveRecord::Base
  belongs_to :location, :foreign_key=>''postal_code''
  validates_presence_of :name, :postal_code
end
---

location.rb
---
class Location < ActiveRecord::Base
  has_many :customers
end
---

The locations table is filled with >300,000 records.
The customers table has a couple of records with postal_codes that
match the locations table.

In the controller, I have...
---
  def test
    @customer = Customer.find(1)
  end
---

In the view, I have...
---
<%= @customer.name %>
---
...which yields the first name-record in the customers table, so that''s
OK.

But shouldn''t I be able to now do something like:
---
<%= @customer.location.latitude %>
---
...and expect it to return the corresponding latitude from the locations table?

I get the nil error:
---
"You have a nil object when you didn''t expect it!
The error occured while evaluating nil.latitude"
---

What could be wrong?
Is it something with the way I''ve set up the alternative foreign-key?
or is it a plural/singular naming problem?

Thanks for any help.

Gijs Nijholt

njmacinnes@gmail.com

2006-May-24 14:09 UTC

head link

[Rails] AR foreign key problem.

Replace the postal_code field in customers with a postal_code_id int
field, then you should be able to get that working.
-N

On 24/05/06, Gijs Nijholt <gijs.nijholt@gmail.com>
wrote:> Hello Railslist,
>
> (I''m using RadRails 0.6.3 on Windows XP with Ruby 1.8.4, Rails 1.1
and SQLite3)
>
> I have two tables in the database: "locations" and
"customers":
>
> customers.sql
> ---
> id INT PRIMARY KEY
> name VARCHAR 255
> address VARCHAR 255
> postal_code VARCHAR 255
> city VARCHAR 255
> ---
>
> locations.sql
> ---
> id INT PRIMARY KEY
> postal_code TEXT
> longitude FLOAT
> latitude FLOAT
> ---
>
>
> I''ve created two models (customer.rb and location.rb):
>
> customer.rb
> ---
> class Customer < ActiveRecord::Base
>  belongs_to :location, :foreign_key=>''postal_code''
>  validates_presence_of :name, :postal_code
> end
> ---
>
> location.rb
> ---
> class Location < ActiveRecord::Base
>  has_many :customers
> end
> ---
>
> The locations table is filled with >300,000 records.
> The customers table has a couple of records with postal_codes that
> match the locations table.
>
> In the controller, I have...
> ---
>  def test
>    @customer = Customer.find(1)
>  end
> ---
>
> In the view, I have...
> ---
> <%= @customer.name %>
> ---
> ...which yields the first name-record in the customers table, so
that''s OK.
>
> But shouldn''t I be able to now do something like:
> ---
> <%= @customer.location.latitude %>
> ---
> ...and expect it to return the corresponding latitude from the locations
table?
>
> I get the nil error:
> ---
> "You have a nil object when you didn''t expect it!
> The error occured while evaluating nil.latitude"
> ---
>
> What could be wrong?
> Is it something with the way I''ve set up the alternative
foreign-key?
> or is it a plural/singular naming problem?
>
> Thanks for any help.
>
> Gijs Nijholt
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>

Gijs Nijholt

2006-May-24 14:54 UTC

head link

[Rails] AR foreign key problem.

does the table postal_code_in need to be of type INT per se?
I still get exactly the same error (nil object) as before (I restarted webrick)


On 5/24/06, njmacinnes@gmail.com <njmacinnes@gmail.com>
wrote:> Replace the postal_code field in customers with a postal_code_id int
> field, then you should be able to get that working.
> -N
>
> On 24/05/06, Gijs Nijholt <gijs.nijholt@gmail.com> wrote:
> > Hello Railslist,
> >
> > (I''m using RadRails 0.6.3 on Windows XP with Ruby 1.8.4,
Rails 1.1 and SQLite3)
> >
> > I have two tables in the database: "locations" and
"customers":
> >
> > customers.sql
> > ---
> > id INT PRIMARY KEY
> > name VARCHAR 255
> > address VARCHAR 255
> > postal_code VARCHAR 255
> > city VARCHAR 255
> > ---
> >
> > locations.sql
> > ---
> > id INT PRIMARY KEY
> > postal_code TEXT
> > longitude FLOAT
> > latitude FLOAT
> > ---
> >
> >
> > I''ve created two models (customer.rb and location.rb):
> >
> > customer.rb
> > ---
> > class Customer < ActiveRecord::Base
> >  belongs_to :location,
:foreign_key=>''postal_code''
> >  validates_presence_of :name, :postal_code
> > end
> > ---
> >
> > location.rb
> > ---
> > class Location < ActiveRecord::Base
> >  has_many :customers
> > end
> > ---
> >
> > The locations table is filled with >300,000 records.
> > The customers table has a couple of records with postal_codes that
> > match the locations table.
> >
> > In the controller, I have...
> > ---
> >  def test
> >    @customer = Customer.find(1)
> >  end
> > ---
> >
> > In the view, I have...
> > ---
> > <%= @customer.name %>
> > ---
> > ...which yields the first name-record in the customers table, so
that''s OK.
> >
> > But shouldn''t I be able to now do something like:
> > ---
> > <%= @customer.location.latitude %>
> > ---
> > ...and expect it to return the corresponding latitude from the
locations table?
> >
> > I get the nil error:
> > ---
> > "You have a nil object when you didn''t expect it!
> > The error occured while evaluating nil.latitude"
> > ---
> >
> > What could be wrong?
> > Is it something with the way I''ve set up the alternative
foreign-key?
> > or is it a plural/singular naming problem?
> >
> > Thanks for any help.
> >
> > Gijs Nijholt
> >
> > _______________________________________________
> > 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
>

jatinder saundh

2006-May-25 06:26 UTC

head link

[Rails] AR foreign key problem.

1. postal_code column in both the tables should be of same type
if that is not working then having a location_id column in customers table,
referring to id column of locations table will surely work; with this you
can skip :foreign_key option, Rails will take care of that.

Regards,
Jatinder


On 5/24/06, Gijs Nijholt <gijs.nijholt@gmail.com>
wrote:>
> does the table postal_code_in need to be of type INT per se?
> I still get exactly the same error (nil object) as before (I restarted
> webrick)
>
>
> On 5/24/06, njmacinnes@gmail.com <njmacinnes@gmail.com> wrote:
> > Replace the postal_code field in customers with a postal_code_id int
> > field, then you should be able to get that working.
> > -N
> >
> > On 24/05/06, Gijs Nijholt <gijs.nijholt@gmail.com> wrote:
> > > Hello Railslist,
> > >
> > > (I''m using RadRails 0.6.3 on Windows XP with Ruby 1.8.4,
Rails 1.1 and
> SQLite3)
> > >
> > > I have two tables in the database: "locations" and
"customers":
> > >
> > > customers.sql
> > > ---
> > > id INT PRIMARY KEY
> > > name VARCHAR 255
> > > address VARCHAR 255
> > > postal_code VARCHAR 255
> > > city VARCHAR 255
> > > ---
> > >
> > > locations.sql
> > > ---
> > > id INT PRIMARY KEY
> > > postal_code TEXT
> > > longitude FLOAT
> > > latitude FLOAT
> > > ---
> > >
> > >
> > > I''ve created two models (customer.rb and location.rb):
> > >
> > > customer.rb
> > > ---
> > > class Customer < ActiveRecord::Base
> > >  belongs_to :location,
:foreign_key=>''postal_code''
> > >  validates_presence_of :name, :postal_code
> > > end
> > > ---
> > >
> > > location.rb
> > > ---
> > > class Location < ActiveRecord::Base
> > >  has_many :customers
> > > end
> > > ---
> > >
> > > The locations table is filled with >300,000 records.
> > > The customers table has a couple of records with postal_codes
that
> > > match the locations table.
> > >
> > > In the controller, I have...
> > > ---
> > >  def test
> > >    @customer = Customer.find(1)
> > >  end
> > > ---
> > >
> > > In the view, I have...
> > > ---
> > > <%= @customer.name %>
> > > ---
> > > ...which yields the first name-record in the customers table, so
> that''s OK.
> > >
> > > But shouldn''t I be able to now do something like:
> > > ---
> > > <%= @customer.location.latitude %>
> > > ---
> > > ...and expect it to return the corresponding latitude from the
> locations table?
> > >
> > > I get the nil error:
> > > ---
> > > "You have a nil object when you didn''t expect it!
> > > The error occured while evaluating nil.latitude"
> > > ---
> > >
> > > What could be wrong?
> > > Is it something with the way I''ve set up the alternative
foreign-key?
> > > or is it a plural/singular naming problem?
> > >
> > > Thanks for any help.
> > >
> > > Gijs Nijholt
> > >
> > > _______________________________________________
> > > 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
> >
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
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njmacinnes@gmail.com

2006-May-25 13:00 UTC

head link

[Rails] AR foreign key problem.

Oh yeah, that''s what I meant. I was thinking you had a postal_codes
table, because I''ve got one of those. But using an int location_id
would do the job.
-N

On 25/05/06, jatinder saundh <jatinder.saundh@gmail.com>
wrote:>
> 1. postal_code column in both the tables should be of same type
> if that is not working then having a location_id column in customers table,
> referring to id column of locations table will surely work; with this you
> can skip :foreign_key option, Rails will take care of that.
>
> Regards,
> Jatinder
>
>
> On 5/24/06, Gijs Nijholt <gijs.nijholt@gmail.com> wrote:
> > does the table postal_code_in need to be of type INT per se?
> > I still get exactly the same error (nil object) as before (I restarted
> webrick)
> >
> >
> > On 5/24/06, njmacinnes@gmail.com <njmacinnes@gmail.com> wrote:
> > > Replace the postal_code field in customers with a postal_code_id
int
> > > field, then you should be able to get that working.
> > > -N
> > >
> > > On 24/05/06, Gijs Nijholt <gijs.nijholt@gmail.com> wrote:
> > > > Hello Railslist,
> > > >
> > > > (I''m using RadRails 0.6.3 on Windows XP with Ruby
1.8.4, Rails 1.1 and
> SQLite3)
> > > >
> > > > I have two tables in the database: "locations" and
"customers":
> > > >
> > > > customers.sql
> > > > ---
> > > > id INT PRIMARY KEY
> > > > name VARCHAR 255
> > > > address VARCHAR 255
> > > > postal_code VARCHAR 255
> > > > city VARCHAR 255
> > > > ---
> > > >
> > > > locations.sql
> > > > ---
> > > > id INT PRIMARY KEY
> > > > postal_code TEXT
> > > > longitude FLOAT
> > > > latitude FLOAT
> > > > ---
> > > >
> > > >
> > > > I''ve created two models (customer.rb and
location.rb):
> > > >
> > > > customer.rb
> > > > ---
> > > > class Customer < ActiveRecord::Base
> > > >  belongs_to :location,
:foreign_key=>''postal_code''
> > > >  validates_presence_of :name, :postal_code
> > > > end
> > > > ---
> > > >
> > > > location.rb
> > > > ---
> > > > class Location < ActiveRecord::Base
> > > >  has_many :customers
> > > > end
> > > > ---
> > > >
> > > > The locations table is filled with >300,000 records.
> > > > The customers table has a couple of records with
postal_codes that
> > > > match the locations table.
> > > >
> > > > In the controller, I have...
> > > > ---
> > > >  def test
> > > >    @customer = Customer.find(1)
> > > >  end
> > > > ---
> > > >
> > > > In the view, I have...
> > > > ---
> > > > <%= @customer.name %>
> > > > ---
> > > > ...which yields the first name-record in the customers
table, so
> that''s OK.
> > > >
> > > > But shouldn''t I be able to now do something like:
> > > > ---
> > > > <%= @customer.location.latitude %>
> > > > ---
> > > > ...and expect it to return the corresponding latitude from
the
> locations table?
> > > >
> > > > I get the nil error:
> > > > ---
> > > > "You have a nil object when you didn''t expect
it!
> > > > The error occured while evaluating nil.latitude"
> > > > ---
> > > >
> > > > What could be wrong?
> > > > Is it something with the way I''ve set up the
alternative foreign-key?
> > > > or is it a plural/singular naming problem?
> > > >
> > > > Thanks for any help.
> > > >
> > > > Gijs Nijholt
> > > >
> > > > _______________________________________________
> > > > 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
> > >
> >
> > _______________________________________________
> > 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
>
>
>

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