Rails - Aug 2010 - Once I added this HABTM, one of my 'through' relationships, on a non-habtm model, seems to have broke?

I''m a rails newb and have been Googling about this, but I''m
still stumped.

Not showing everything here, but basically it should be a pretty common
setup so I''m sure others know what I''m doing wrong.

- A meter can belong to many meter_groups
- A meter_group can have many meters.
- A user can ''subscribe'' to viewing a meter_group
(Subscription) so he
should be able to see the meters that are in that meter_group of the
subscription (think subscribing to a topic in a forum.)

Initially I was only allowing a single meter to belong to only one
meter_group and the following test and relationship of a Subscription worked
fine:

class Subscription < ActiveRecord::Base
  belongs_to :user, :foreign_key => "user_id"
  belongs_to :meter_group, :foreign_key => "meter_group_id"
  has_many :meters, :through => :meter_group
end

test "group1 and group2 belong to rachel" do
    user = User.find_by_login("rachel")
    subscriptions = Subscription.find_all_by_user_id(user.id)
    subscriptions.each do |s|
      meters = s.meters
      meters.each do |m|
        puts "meter = #{p m}"
      end
    end
  end

However now things are not working since I created some HABTM relationships
for meter_group and meters. I end up with the following error:

ActiveRecord::HasManyThroughSourceAssociationMacroError: Invalid source
reflection macro :has_and_belongs_to_many for has_many :meters, :through =>
:meter_group.  Use :source to specify the source reflection.

Here are some of the other relevant tables and migrations (stripped of a few
non-related fields):

class MeterGroup < ActiveRecord::Base
  belongs_to :user, :foreign_key => "user_id"
  has_and_belongs_to_many :meters
end

class Meter < ActiveRecord::Base
  has_and_belongs_to_many :meter_groups
  belongs_to :user, :foreign_key => "user_id"
end

#Migrations (removed some cols and drop section)

class CreateMeterGroups < ActiveRecord::Migration
  def self.up
    create_table :meter_groups do |t|
      t.string :name
      t.string :description
      t.integer :user_id

      t.timestamps
    end
  end
end

class CreateMeters < ActiveRecord::Migration
  def self.up
    create_table :meters do |t|
      t.integer :meter_type_id
      t.integer :scale_id
      t.integer :user_id
      t.string :name
      t.string :description

      t.timestamps
    end
  end
end

class CreateMetersMeterGroups < ActiveRecord::Migration
  def self.up
    create_table :meter_groups_meters, :id => false  do |t|
      t.integer :meter_id
      t.integer :meter_group_id

      t.timestamps
    end
  end
end

class CreateSubscriptions < ActiveRecord::Migration
  def self.up
    create_table :subscriptions do |t|
      t.integer :user_id
      t.integer :meter_group_id

      t.timestamps
    end
  end
end

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On Wed, Aug 18, 2010 at 3:04 PM, Rick R
<rickcr-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> I''m a rails newb and have been Googling about this, but
I''m still stumped.
>
> Not showing everything here, but basically it should be a pretty common
> setup so I''m sure others know what I''m doing wrong.
>
> - A meter can belong to many meter_groups
> - A meter_group can have many meters.
> - A user can ''subscribe'' to viewing a meter_group
(Subscription) so he
> should be able to see the meters that are in that meter_group of the
> subscription (think subscribing to a topic in a forum.)
>
> Initially I was only allowing a single meter to belong to only one
> meter_group and the following test and relationship of a Subscription
worked
> fine:
>
> class Subscription < ActiveRecord::Base
>   belongs_to :user, :foreign_key => "user_id"
>   belongs_to :meter_group, :foreign_key => "meter_group_id"
>   has_many :meters, :through => :meter_group
> end
>
> test "group1 and group2 belong to rachel" do
>     user = User.find_by_login("rachel")
>     subscriptions = Subscription.find_all_by_user_id(user.id)
>     subscriptions.each do |s|
>       meters = s.meters
>       meters.each do |m|
>         puts "meter = #{p m}"
>       end
>     end
>   end
>
>
As a side note, there isn''t an issue if I try to get meters directly
from
the meter_group. For example in the above test it works if changed to:

test "group1 and group2 belong to rachel" do
    user = User.find_by_login("rachel")
    subscriptions = Subscription.find_all_by_user_id(user.id)
    subscriptions.each do |s|
    *meter_group = s.meter_group
    meters = meter_group.meters*
    meters.each do |m|
        puts "meter = #{p m}"
      end
    end
  end



> However now things are not working since I created some HABTM relationships
> for meter_group and meters. I end up with the following error:
>
> ActiveRecord::HasManyThroughSourceAssociationMacroError: Invalid source
> reflection macro :has_and_belongs_to_many for has_many :meters, :through
=>
> :meter_group.  Use :source to specify the source reflection.
>
> Here are some of the other relevant tables and migrations (stripped of a
> few non-related fields):
>
> class MeterGroup < ActiveRecord::Base
>   belongs_to :user, :foreign_key => "user_id"
>   has_and_belongs_to_many :meters
> end
>
> class Meter < ActiveRecord::Base
>   has_and_belongs_to_many :meter_groups
>   belongs_to :user, :foreign_key => "user_id"
> end
>
> #Migrations (removed some cols and drop section)
>
> class CreateMeterGroups < ActiveRecord::Migration
>   def self.up
>     create_table :meter_groups do |t|
>       t.string :name
>       t.string :description
>       t.integer :user_id
>
>       t.timestamps
>     end
>   end
> end
>
> class CreateMeters < ActiveRecord::Migration
>   def self.up
>     create_table :meters do |t|
>       t.integer :meter_type_id
>       t.integer :scale_id
>       t.integer :user_id
>       t.string :name
>       t.string :description
>
>       t.timestamps
>     end
>   end
> end
>
> class CreateMetersMeterGroups < ActiveRecord::Migration
>   def self.up
>     create_table :meter_groups_meters, :id => false  do |t|
>       t.integer :meter_id
>       t.integer :meter_group_id
>
>       t.timestamps
>     end
>   end
> end
>
> class CreateSubscriptions < ActiveRecord::Migration
>   def self.up
>     create_table :subscriptions do |t|
>       t.integer :user_id
>       t.integer :meter_group_id
>
>       t.timestamps
>     end
>   end
> end
>


-- 
Rick R

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I would start by getting rid of the :foreign_key  specifications
unless you are doing something non standard.

On Aug 18, 2:26 pm, Rick R
<ric...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> On Wed, Aug 18, 2010 at 3:04 PM, Rick R
<ric...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > I''m a rails newb and have been Googling about this, but
I''m still stumped.
>
> > Not showing everything here, but basically it should be a pretty
common
> > setup so I''m sure others know what I''m doing wrong.
>
> > - A meter can belong to many meter_groups
> > - A meter_group can have many meters.
> > - A user can ''subscribe'' to viewing a meter_group
(Subscription) so he
> > should be able to see the meters that are in that meter_group of the
> > subscription (think subscribing to a topic in a forum.)
>
> > Initially I was only allowing a single meter to belong to only one
> > meter_group and the following test and relationship of a Subscription
worked
> > fine:
>
> > class Subscription < ActiveRecord::Base
> >   belongs_to :user, :foreign_key => "user_id"
> >   belongs_to :meter_group, :foreign_key =>
"meter_group_id"
> >   has_many :meters, :through => :meter_group
> > end
>
> > test "group1 and group2 belong to rachel" do
> >     user = User.find_by_login("rachel")
> >     subscriptions = Subscription.find_all_by_user_id(user.id)
> >     subscriptions.each do |s|
> >       meters = s.meters
> >       meters.each do |m|
> >         puts "meter = #{p m}"
> >       end
> >     end
> >   end
>
> As a side note, there isn''t an issue if I try to get meters
directly from
> the meter_group. For example in the above test it works if changed to:
>
> test "group1 and group2 belong to rachel" do
>     user = User.find_by_login("rachel")
>     subscriptions = Subscription.find_all_by_user_id(user.id)
>     subscriptions.each do |s|
>     *meter_group = s.meter_group
>     meters = meter_group.meters*
>     meters.each do |m|
>         puts "meter = #{p m}"
>       end
>     end
>   end
>
>
>
>
>
> > However now things are not working since I created some HABTM
relationships
> > for meter_group and meters. I end up with the following error:
>
> > ActiveRecord::HasManyThroughSourceAssociationMacroError: Invalid
source
> > reflection macro :has_and_belongs_to_many for has_many :meters,
:through =>
> > :meter_group.  Use :source to specify the source reflection.
>
> > Here are some of the other relevant tables and migrations (stripped of
a
> > few non-related fields):
>
> > class MeterGroup < ActiveRecord::Base
> >   belongs_to :user, :foreign_key => "user_id"
> >   has_and_belongs_to_many :meters
> > end
>
> > class Meter < ActiveRecord::Base
> >   has_and_belongs_to_many :meter_groups
> >   belongs_to :user, :foreign_key => "user_id"
> > end
>
> > #Migrations (removed some cols and drop section)
>
> > class CreateMeterGroups < ActiveRecord::Migration
> >   def self.up
> >     create_table :meter_groups do |t|
> >       t.string :name
> >       t.string :description
> >       t.integer :user_id
>
> >       t.timestamps
> >     end
> >   end
> > end
>
> > class CreateMeters < ActiveRecord::Migration
> >   def self.up
> >     create_table :meters do |t|
> >       t.integer :meter_type_id
> >       t.integer :scale_id
> >       t.integer :user_id
> >       t.string :name
> >       t.string :description
>
> >       t.timestamps
> >     end
> >   end
> > end
>
> > class CreateMetersMeterGroups < ActiveRecord::Migration
> >   def self.up
> >     create_table :meter_groups_meters, :id => false  do |t|
> >       t.integer :meter_id
> >       t.integer :meter_group_id
>
> >       t.timestamps
> >     end
> >   end
> > end
>
> > class CreateSubscriptions < ActiveRecord::Migration
> >   def self.up
> >     create_table :subscriptions do |t|
> >       t.integer :user_id
> >       t.integer :meter_group_id
>
> >       t.timestamps
> >     end
> >   end
> > end
>
> --
> Rick R
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On Wed, Aug 18, 2010 at 3:30 PM, Me
<chabgood-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> I would start by getting rid of the :foreign_key  specifications
> unless you are doing something non standard.
>
>
Ok, thanks. I removed them. (Didn''t fix the issue but does look a lot
cleaner.)

> On Aug 18, 2:26 pm, Rick R
<ric...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > On Wed, Aug 18, 2010 at 3:04 PM, Rick R
<ric...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > I''m a rails newb and have been Googling about this, but
I''m still
> stumped.
> >
> > > Not showing everything here, but basically it should be a pretty
common
> > > setup so I''m sure others know what I''m doing
wrong.
> >
> > > - A meter can belong to many meter_groups
> > > - A meter_group can have many meters.
> > > - A user can ''subscribe'' to viewing a
meter_group (Subscription) so he
> > > should be able to see the meters that are in that meter_group of
the
> > > subscription (think subscribing to a topic in a forum.)
> >
> > > Initially I was only allowing a single meter to belong to only
one
> > > meter_group and the following test and relationship of a
Subscription
> worked
> > > fine:
> >
> > > class Subscription < ActiveRecord::Base
> > >   belongs_to :user, :foreign_key => "user_id"
> > >   belongs_to :meter_group, :foreign_key =>
"meter_group_id"
> > >   has_many :meters, :through => :meter_group
> > > end
> >
> > > test "group1 and group2 belong to rachel" do
> > >     user = User.find_by_login("rachel")
> > >     subscriptions = Subscription.find_all_by_user_id(user.id)
> > >     subscriptions.each do |s|
> > >       meters = s.meters
> > >       meters.each do |m|
> > >         puts "meter = #{p m}"
> > >       end
> > >     end
> > >   end
> >
> > As a side note, there isn''t an issue if I try to get meters
directly from
> > the meter_group. For example in the above test it works if changed to:
> >
> > test "group1 and group2 belong to rachel" do
> >     user = User.find_by_login("rachel")
> >     subscriptions = Subscription.find_all_by_user_id(user.id)
> >     subscriptions.each do |s|
> >     *meter_group = s.meter_group
> >     meters = meter_group.meters*
> >     meters.each do |m|
> >         puts "meter = #{p m}"
> >       end
> >     end
> >   end
> >
> >
> >
> >
> >
> > > However now things are not working since I created some HABTM
> relationships
> > > for meter_group and meters. I end up with the following error:
> >
> > > ActiveRecord::HasManyThroughSourceAssociationMacroError: Invalid
source
> > > reflection macro :has_and_belongs_to_many for has_many :meters,
> :through =>
> > > :meter_group.  Use :source to specify the source reflection.
> >
> > > Here are some of the other relevant tables and migrations
(stripped of
> a
> > > few non-related fields):
> >
> > > class MeterGroup < ActiveRecord::Base
> > >   belongs_to :user, :foreign_key => "user_id"
> > >   has_and_belongs_to_many :meters
> > > end
> >
> > > class Meter < ActiveRecord::Base
> > >   has_and_belongs_to_many :meter_groups
> > >   belongs_to :user, :foreign_key => "user_id"
> > > end
> >
> > > #Migrations (removed some cols and drop section)
> >
> > > class CreateMeterGroups < ActiveRecord::Migration
> > >   def self.up
> > >     create_table :meter_groups do |t|
> > >       t.string :name
> > >       t.string :description
> > >       t.integer :user_id
> >
> > >       t.timestamps
> > >     end
> > >   end
> > > end
> >
> > > class CreateMeters < ActiveRecord::Migration
> > >   def self.up
> > >     create_table :meters do |t|
> > >       t.integer :meter_type_id
> > >       t.integer :scale_id
> > >       t.integer :user_id
> > >       t.string :name
> > >       t.string :description
> >
> > >       t.timestamps
> > >     end
> > >   end
> > > end
> >
> > > class CreateMetersMeterGroups < ActiveRecord::Migration
> > >   def self.up
> > >     create_table :meter_groups_meters, :id => false  do |t|
> > >       t.integer :meter_id
> > >       t.integer :meter_group_id
> >
> > >       t.timestamps
> > >     end
> > >   end
> > > end
> >
> > > class CreateSubscriptions < ActiveRecord::Migration
> > >   def self.up
> > >     create_table :subscriptions do |t|
> > >       t.integer :user_id
> > >       t.integer :meter_group_id
> >
> > >       t.timestamps
> > >     end
> > >   end
> > > end
> >
> > --
> > Rick R
>
> --
> You received this message because you are subscribed to the Google Groups
> "Ruby on Rails: Talk" group.
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> .
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>
>

-- 
Rick R

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oh you need to add the has_many for the join table

has_many :meter_goup
has_many :meters, :through => :meter_group

On Aug 18, 2:41 pm, Rick R
<ric...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> On Wed, Aug 18, 2010 at 3:30 PM, Me
<chabg...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > I would start by getting rid of the :foreign_key  specifications
> > unless you are doing something non standard.
>
> Ok, thanks. I removed them. (Didn''t fix the issue but does look a
lot
> cleaner.)
>
>
>
>
>
> > On Aug 18, 2:26 pm, Rick R
<ric...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > On Wed, Aug 18, 2010 at 3:04 PM, Rick R
<ric...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > > I''m a rails newb and have been Googling about this,
but I''m still
> > stumped.
>
> > > > Not showing everything here, but basically it should be a
pretty common
> > > > setup so I''m sure others know what I''m
doing wrong.
>
> > > > - A meter can belong to many meter_groups
> > > > - A meter_group can have many meters.
> > > > - A user can ''subscribe'' to viewing a
meter_group (Subscription) so he
> > > > should be able to see the meters that are in that
meter_group of the
> > > > subscription (think subscribing to a topic in a forum.)
>
> > > > Initially I was only allowing a single meter to belong to
only one
> > > > meter_group and the following test and relationship of a
Subscription
> > worked
> > > > fine:
>
> > > > class Subscription < ActiveRecord::Base
> > > >   belongs_to :user, :foreign_key => "user_id"
> > > >   belongs_to :meter_group, :foreign_key =>
"meter_group_id"
> > > >   has_many :meters, :through => :meter_group
> > > > end
>
> > > > test "group1 and group2 belong to rachel" do
> > > >     user = User.find_by_login("rachel")
> > > >     subscriptions =
Subscription.find_all_by_user_id(user.id)
> > > >     subscriptions.each do |s|
> > > >       meters = s.meters
> > > >       meters.each do |m|
> > > >         puts "meter = #{p m}"
> > > >       end
> > > >     end
> > > >   end
>
> > > As a side note, there isn''t an issue if I try to get
meters directly from
> > > the meter_group. For example in the above test it works if
changed to:
>
> > > test "group1 and group2 belong to rachel" do
> > >     user = User.find_by_login("rachel")
> > >     subscriptions = Subscription.find_all_by_user_id(user.id)
> > >     subscriptions.each do |s|
> > >     *meter_group = s.meter_group
> > >     meters = meter_group.meters*
> > >     meters.each do |m|
> > >         puts "meter = #{p m}"
> > >       end
> > >     end
> > >   end
>
> > > > However now things are not working since I created some
HABTM
> > relationships
> > > > for meter_group and meters. I end up with the following
error:
>
> > > > ActiveRecord::HasManyThroughSourceAssociationMacroError:
Invalid source
> > > > reflection macro :has_and_belongs_to_many for has_many
:meters,
> > :through =>
> > > > :meter_group.  Use :source to specify the source reflection.
>
> > > > Here are some of the other relevant tables and migrations
(stripped of
> > a
> > > > few non-related fields):
>
> > > > class MeterGroup < ActiveRecord::Base
> > > >   belongs_to :user, :foreign_key => "user_id"
> > > >   has_and_belongs_to_many :meters
> > > > end
>
> > > > class Meter < ActiveRecord::Base
> > > >   has_and_belongs_to_many :meter_groups
> > > >   belongs_to :user, :foreign_key => "user_id"
> > > > end
>
> > > > #Migrations (removed some cols and drop section)
>
> > > > class CreateMeterGroups < ActiveRecord::Migration
> > > >   def self.up
> > > >     create_table :meter_groups do |t|
> > > >       t.string :name
> > > >       t.string :description
> > > >       t.integer :user_id
>
> > > >       t.timestamps
> > > >     end
> > > >   end
> > > > end
>
> > > > class CreateMeters < ActiveRecord::Migration
> > > >   def self.up
> > > >     create_table :meters do |t|
> > > >       t.integer :meter_type_id
> > > >       t.integer :scale_id
> > > >       t.integer :user_id
> > > >       t.string :name
> > > >       t.string :description
>
> > > >       t.timestamps
> > > >     end
> > > >   end
> > > > end
>
> > > > class CreateMetersMeterGroups < ActiveRecord::Migration
> > > >   def self.up
> > > >     create_table :meter_groups_meters, :id => false  do
|t|
> > > >       t.integer :meter_id
> > > >       t.integer :meter_group_id
>
> > > >       t.timestamps
> > > >     end
> > > >   end
> > > > end
>
> > > > class CreateSubscriptions < ActiveRecord::Migration
> > > >   def self.up
> > > >     create_table :subscriptions do |t|
> > > >       t.integer :user_id
> > > >       t.integer :meter_group_id
>
> > > >       t.timestamps
> > > >     end
> > > >   end
> > > > end
>
> > > --
> > > Rick R
>
> > --
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> Rick R
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On Wed, Aug 18, 2010 at 4:00 PM, Me
<chabgood-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> oh you need to add the has_many for the join table
>
> has_many :meter_goup
> has_many :meters, :through => :meter_group
>
>
I take it you mean on the Subscription table? which currently looks like:

class Subscription < ActiveRecord::Base
  belongs_to :user
  belongs_to :meter_group
  has_many :meters, :through => :meter_group
end

But a Subscription doesn''t have many mete groups, a subscription can
only be
tied to a single meterGroup and has a fk to the meter_group table.

Or are you saying for the other join table "meter_groups_meters" I
need to
make a MeterGroupsMeter model object and add the relationships you
described?

For reference The other relevant tables are:

class Meter < ActiveRecord::Base
  has_and_belongs_to_many :meter_groups
  belongs_to :user
end

class MeterGroup < ActiveRecord::Base
  belongs_to :user
  has_and_belongs_to_many :meters
end

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sorry I misread your tables.  The has_many :through is looking for a
join table with ids for both sides which is the cause of the error,
same kind of table as a HABTM join table.

class Author < ActiveRecord::Base
    has_many :authorships
    has_many :books, :through => :authorships
  end

  class Authorship < ActiveRecord::Base
    belongs_to :author
    belongs_to :book
  end


On Aug 18, 3:43 pm, Rick R
<ric...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> On Wed, Aug 18, 2010 at 4:00 PM, Me
<chabg...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > oh you need to add the has_many for the join table
>
> > has_many :meter_goup
> > has_many :meters, :through => :meter_group
>
> I take it you mean on the Subscription table? which currently looks like:
>
> class Subscription < ActiveRecord::Base
>   belongs_to :user
>   belongs_to :meter_group
>   has_many :meters, :through => :meter_group
> end
>
> But a Subscription doesn''t have many mete groups, a subscription
can only be
> tied to a single meterGroup and has a fk to the meter_group table.
>
> Or are you saying for the other join table "meter_groups_meters"
I need to
> make a MeterGroupsMeter model object and add the relationships you
> described?
>
> For reference The other relevant tables are:
>
> class Meter < ActiveRecord::Base
>   has_and_belongs_to_many :meter_groups
>   belongs_to :user
> end
>
> class MeterGroup < ActiveRecord::Base
>   belongs_to :user
>   has_and_belongs_to_many :meters
> end
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