Rails - Sep 2010 - Creating a Scope that joins user_id with the User Table (user.id) — Rails 3

Hello, I''m using Rails 3 with devise.

I have a table books which has a column for user_id, which is related
to the Users table (user.rb) (FK)

I''m trying to create a Scope that shows all the books along with the
user''s email address (Books joined to Users)
Example: Title, Content, User.Email

class Book < ActiveRecord::Base
 scope :personal, proc {|user| where(:user_id => user.id) }
end

Can you help me understand why this is erroring with: "Called id for
nil, which would mistakenly be 4 -- if you really wanted the id of
nil, use object_id"

thanks

-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

Are you passing the argument when calling Book.peronal? I think it
expects something like this Book.personal(User.first) -- you can
replace User.first by any instance of the class User.

On Sep 12, 11:57 am, nobosh
<bhellm...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Hello, I''m using Rails 3 with devise.
>
> I have a table books which has a column for user_id, which is related
> to the Users table (user.rb) (FK)
>
> I''m trying to create a Scope that shows all the books along with
the
> user''s email address (Books joined to Users)
> Example: Title, Content, User.Email
>
> class Book < ActiveRecord::Base
>  scope :personal, proc {|user| where(:user_id => user.id) }
> end
>
> Can you help me understand why this is erroring with: "Called id for
> nil, which would mistakenly be 4 -- if you really wanted the id of
> nil, use object_id"
>
> thanks
-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

you are not passing the user post the controller code

On Sun, Sep 12, 2010 at 2:43 PM, saljamil
<salem.m.jamil-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Are you passing the argument when calling Book.peronal? I think it
> expects something like this Book.personal(User.first) -- you can
> replace User.first by any instance of the class User.
>
> On Sep 12, 11:57 am, nobosh
<bhellm...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > Hello, I''m using Rails 3 with devise.
> >
> > I have a table books which has a column for user_id, which is related
> > to the Users table (user.rb) (FK)
> >
> > I''m trying to create a Scope that shows all the books along
with the
> > user''s email address (Books joined to Users)
> > Example: Title, Content, User.Email
> >
> > class Book < ActiveRecord::Base
> >  scope :personal, proc {|user| where(:user_id => user.id) }
> > end
> >
> > Can you help me understand why this is erroring with: "Called id
for
> > nil, which would mistakenly be 4 -- if you really wanted the id of
> > nil, use object_id"
> >
> > thanks
>
> --
> You received this message because you are subscribed to the Google Groups
> "Ruby on Rails: Talk" group.
> To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> To unsubscribe from this group, send email to
>
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
> .
> For more options, visit this group at
> http://groups.google.com/group/rubyonrails-talk?hl=en.
>
>
-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

Thanks looks like I was confusing this.


What I want is to output a query that consists of books joined to the
used, example data row:
book.id, book.name, book.content, user.name, user.id

Right now in Rails everything is just one table, I haven''t learned how
to do joins. How is that done, is that with scopes?


On Sep 12, 12:11 pm, radhames brito
<rbri...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> you are not passing the user post the controller code
>
>
>
> On Sun, Sep 12, 2010 at 2:43 PM, saljamil
<salem.m.ja...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > Are you passing the argument when calling Book.peronal? I think it
> > expects something like this Book.personal(User.first) -- you can
> > replace User.first by any instance of the class User.
>
> > On Sep 12, 11:57 am, nobosh
<bhellm...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > Hello, I''m using Rails 3 with devise.
>
> > > I have a table books which has a column for user_id, which is
related
> > > to the Users table (user.rb) (FK)
>
> > > I''m trying to create a Scope that shows all the books
along with the
> > > user''s email address (Books joined to Users)
> > > Example: Title, Content, User.Email
>
> > > class Book < ActiveRecord::Base
> > >  scope :personal, proc {|user| where(:user_id => user.id) }
> > > end
>
> > > Can you help me understand why this is erroring with:
"Called id for
> > > nil, which would mistakenly be 4 -- if you really wanted the id
of
> > > nil, use object_id"
>
> > > thanks
>
> > --
> > You received this message because you are subscribed to the Google
Groups
> > "Ruby on Rails: Talk" group.
> > To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> > To unsubscribe from this group, send email to
> >
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscrib
e@googlegroups.com>
> > .
> > For more options, visit this group at
> >http://groups.google.com/group/rubyonrails-talk?hl=en.
-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

Ok, so I can do something like this:
scope :expandedvv, Book.joins(:user)

Which has the query (from the dev log) showing:
SELECT "books".* FROM "books" INNER JOIN "users"
ON "users"."id" "books"."user_id" ORDER
BY books.created_at DESC

Problem is it isn''t selecting the fields from the User table that I
need, user.name

Ideas?



On Sep 12, 3:19 pm, nobosh
<bhellm...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Thanks looks like I was confusing this.
>
> What I want is to output a query that consists of books joined to the
> used, example data row:
> book.id, book.name, book.content, user.name, user.id
>
> Right now in Rails everything is just one table, I haven''t learned
how
> to do joins. How is that done, is that with scopes?
>
> On Sep 12, 12:11 pm, radhames brito
<rbri...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
>
>
> > you are not passing the user post the controller code
>
> > On Sun, Sep 12, 2010 at 2:43 PM, saljamil
<salem.m.ja...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > Are you passing the argument when calling Book.peronal? I think
it
> > > expects something like this Book.personal(User.first) -- you can
> > > replace User.first by any instance of the class User.
>
> > > On Sep 12, 11:57 am, nobosh
<bhellm...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > > Hello, I''m using Rails 3 with devise.
>
> > > > I have a table books which has a column for user_id, which
is related
> > > > to the Users table (user.rb) (FK)
>
> > > > I''m trying to create a Scope that shows all the
books along with the
> > > > user''s email address (Books joined to Users)
> > > > Example: Title, Content, User.Email
>
> > > > class Book < ActiveRecord::Base
> > > >  scope :personal, proc {|user| where(:user_id => user.id)
}
> > > > end
>
> > > > Can you help me understand why this is erroring with:
"Called id for
> > > > nil, which would mistakenly be 4 -- if you really wanted the
id of
> > > > nil, use object_id"
>
> > > > thanks
>
> > > --
> > > You received this message because you are subscribed to the
Google Groups
> > > "Ruby on Rails: Talk" group.
> > > To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh4Ykp1iOSErHA@public.gmane.orgm.
> > > To unsubscribe from this group, send email to
> > >
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscrib
e@googlegroups.com>
> > > .
> > > For more options, visit this group at
> > >http://groups.google.com/group/rubyonrails-talk?hl=en.
-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

While you could change your scope to:

scope: expandedvv, Book.select(''books.*,
users.name'').joins(:user)

You could also use (assuming you''ve correctly defined the
relationships between your book and user models) the activerecord
functionality to display the associated user''s info in your output,
for example, while iterating through your books using "@books.each do |
book|", you could easily output related user info with book.user.id
and book.user.name.


On Sep 13, 12:39 am, nobosh
<bhellm...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Ok, so I can do something like this:
> scope :expandedvv, Book.joins(:user)
>
> Which has the query (from the dev log) showing:
> SELECT "books".* FROM "books" INNER JOIN
"users" ON "users"."id" >
"books"."user_id" ORDER BY books.created_at DESC
>
> Problem is it isn''t selecting the fields from the User table that
I
> need, user.name
>
> Ideas?
>
> On Sep 12, 3:19 pm, nobosh
<bhellm...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
>
>
> > Thanks looks like I was confusing this.
>
> > What I want is to output a query that consists of books joined to the
> > used, example data row:
> > book.id, book.name, book.content, user.name, user.id
>
> > Right now in Rails everything is just one table, I haven''t
learned how
> > to do joins. How is that done, is that with scopes?
>
> > On Sep 12, 12:11 pm, radhames brito
<rbri...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> > > you are not passing the user post the controller code
>
> > > On Sun, Sep 12, 2010 at 2:43 PM, saljamil
<salem.m.ja...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > > Are you passing the argument when calling Book.peronal? I
think it
> > > > expects something like this Book.personal(User.first) -- you
can
> > > > replace User.first by any instance of the class User.
>
> > > > On Sep 12, 11:57 am, nobosh
<bhellm...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > > > > Hello, I''m using Rails 3 with devise.
>
> > > > > I have a table books which has a column for user_id,
which is related
> > > > > to the Users table (user.rb) (FK)
>
> > > > > I''m trying to create a Scope that shows all
the books along with the
> > > > > user''s email address (Books joined to Users)
> > > > > Example: Title, Content, User.Email
>
> > > > > class Book < ActiveRecord::Base
> > > > >  scope :personal, proc {|user| where(:user_id =>
user.id) }
> > > > > end
>
> > > > > Can you help me understand why this is erroring with:
"Called id for
> > > > > nil, which would mistakenly be 4 -- if you really
wanted the id of
> > > > > nil, use object_id"
>
> > > > > thanks
>
> > > > --
> > > > You received this message because you are subscribed to the
Google Groups
> > > > "Ruby on Rails: Talk" group.
> > > > To post to this group, send email to
rubyonrails-talk@googlegroups.com.
> > > > To unsubscribe from this group, send email to
> > > >
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscrib
e@googlegroups.com>
> > > > .
> > > > For more options, visit this group at
> > > >http://groups.google.com/group/rubyonrails-talk?hl=en.
-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.