Rails - Apr 2011 - trying to seed data from seeds.rb within a class structure

Hey all,

I created this in seeds.rb because I want to avoid duplication as much
as possible:

class DataGenerator
  def initialize
    @current_user = User.first
  end

  def posts!
    Title.each do |t|
      Body.each do |b|
        post! t, b, @current_user.id
      end
    end
  end
end

class StaticDataGenerator < DataGenerator
  def initialize
    super
    @created_at = "2011-04-04".to_date
    @updated_at = "2011-05-04".to_date
    @published = false
  end

  def post!(title, body, user_id, options = {})
    defaults = {
      :title => title,
      :body => body,
      :created => @created_at,
      :updated => @updated_at,
      :published => @published,
      :user_id => user_id
    }
    blog_post = BlogPost.create!(defaults.merge(options))
  end
end

class RandomDataGenerator < DataGenerator
  def initialize
    super
  end
end

Title = ["ABC","DEF","GHI","JKL"]
Body = ["MNO","PQR","STU","VWX"]


So basically what should happen is a new blog_posts record is written to
the database populated with default values like in the following sql
statement:
INSERT INTO blog_posts
(title,body,created_at,updated_at,published,user_id)
VALUES("ABC","MNO",2011-04-04,2011-05-04,0,1)

However, when I run rake db:seed, nothing happens. I suspect that it''s
the class structure of my script that''s not being triggered when I run
db:seed. Any idea how to address this?

Thanks for response.

-- 
Posted via http://www.ruby-forum.com/.

-- 
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.

Have you tried adding:

  StaticDataGenerator.new.posts!

to the end of your file?

-- 
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.

On Tue, Apr 5, 2011 at 2:34 PM, Kendall Gifford
<zettabyte-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Have you tried adding:
>
>   StaticDataGenerator.new.posts!
>
Yeah, that would make sense. I have run into that before where validation or
something fails. BYW, does anyone know if there is a way to invoke the
debugger during rake db:seed or for that matter any other rake task? I dont
think I have ever been successful at this. Maybe have to include ruby-debug
or the like?
>
> to the end of your file?
>
>  --
> 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.
>
-- 
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.

On Tue, Apr 5, 2011 at 3:45 PM, David Kahn
<dk-rfEMNHKVqOwNic7Bib+Ti1W1rNmOCjRP@public.gmane.org>wrote:
>
>
> On Tue, Apr 5, 2011 at 2:34 PM, Kendall Gifford
<zettabyte-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>wrote:
>
>> Have you tried adding:
>>
>>   StaticDataGenerator.new.posts!
>>
>
> Yeah, that would make sense. I have run into that before where validation
> or something fails. BYW, does anyone know if there is a way to invoke the
> debugger during rake db:seed or for that matter any other rake task? I dont
> think I have ever been successful at this. Maybe have to include ruby-debug
> or the like?
>
You can add --trace to the end of your rake command. It''s not a debug
per se
but will show you what is going on with the rake command at the time. I also
like to add a puts statement at the beginning of any call in my rake file.
Something like "Begin seeding posts..." then on the next call
"Begin seeding
comments...". It helps when you didn''t or forgot to add the
--trace flag to
see where you are in the process in case it hangs.

B.

-- 
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.

Kendall Gifford wrote in post #991124:
> Have you tried adding:
>
>   StaticDataGenerator.new.posts!
>
> to the end of your file?
Thanks for response. yes, that worked. That makes sense that you need to 
call a method in client code for it to do anything. I do have one 
unexpected result. This method right here:

  def posts!
    Title.each do |t|
      Body.each do |b|
        post! t, b, @current_user.id
      end
    end
  end


I was expecting it to generate a combination like this:
"ABC" "MNO"
"DEF" "PQR"
"GHI" "STU"
"JKL" "VWX"


See how it corresponds index 0 of the Title array with index 0 of the 
Body array and then index 1 of the Title array with index 1 of the Body 
array and so forth.

But what my posts! method does is this:

"ABC" "MNO"
"ABC" "PQR"
"ABC" "STU"
"ABC" "VWX"
"DEF" "MNO"
"DEF" "PQR"
"DEF" "STU"
"DEF" "VWX"

and so forth. See how it generates index 0 of Title with all the indexes 
of Body and does it for the other indexes of Title as well.

I believe it''s my misunderstanding of the nested block:

   Title.each do |t|
      Body.each do |b|
        post! t, b, @current_user.id
      end
    end

I thought this would iterate through the first index of Title as local 
variable t and then iterate through first index of Body as local 
variable b and then pass them into argument list of post! And then when 
the outer block ended, it would go to the next index and repeat same 
process

Anyone know what I am doing wrong and how to get it to match index to 
index not index to all the other indexes?

Thanks for response.

-- 
Posted via http://www.ruby-forum.com/.

-- 
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.

On Tuesday, April 5, 2011 4:37:58 PM UTC-6, Ruby-Forum.com User
wrote:
>
> Kendall Gifford wrote in post #991124:
> > Have you tried adding:
> >
> >   StaticDataGenerator.new.posts!
> >
> > to the end of your file?
>
> Thanks for response. yes, that worked.
>
 Cool.
> That makes sense that you need to 
> call a method in client code for it to do anything. I do have one 
> unexpected result. This method right here:
>
>   def posts!
>     Title.each do |t|
>       Body.each do |b|
>         post! t, b, @current_user.id
>       end
>     end
>   end
>
>
> I was expecting it to generate a combination like this:
> "ABC" "MNO"
> "DEF" "PQR"
> "GHI" "STU"
> "JKL" "VWX"
>
>
> See how it corresponds index 0 of the Title array with index 0 of the 
> Body array and then index 1 of the Title array with index 1 of the Body 
> array and so forth.
>
But what my posts! method does is this:
>
> "ABC" "MNO"
> "ABC" "PQR"
> "ABC" "STU"
> "ABC" "VWX"
> "DEF" "MNO"
> "DEF" "PQR"
> "DEF" "STU"
> "DEF" "VWX"
>
> and so forth. See how it generates index 0 of Title with all the indexes 
> of Body and does it for the other indexes of Title as well.
>
> I believe it''s my misunderstanding of the nested block:
>
>    Title.each do |t|
>       Body.each do |b|
>         post! t, b, @current_user.id
>       end
>     end
>
Yes, what you were expecting would have been "parallel iteration" (any
experts know if there is a more correct term for this?). What you did was 
"nested iteration" (?). In nested iteration (what you did) your
variables at
your "innermost" scope will, over the course of the iterations,
describe the
"cartesian product" (http://en.wikipedia.org/wiki/Cartesian_product)
of the
sets that you''re iterating over. So, with two sets a and b, the total
number
of combinations (tuples) will be a.length * b.length.

I thought this would iterate through the first index of Title as local
> variable t and then iterate through first index of Body as local 
> variable b and then pass them into argument list of post! And then when 
> the outer block ended, it would go to the next index and repeat same 
> process
>
> Anyone know what I am doing wrong and how to get it to match index to 
> index not index to all the other indexes?
>
One way to do what you want would be (assuming Title and Body will always 
contain the same number of elements):

  def posts!
    Title.each_with_index do |t, i|
      post! t, Body[i], @current_user.id
    end
  end
 
I''m sure there are more clever, ruby-ish ways for parallel iteration
that
using #each_with_index.

P.S. - (nyone feel free to correct this or comment if I''m wrong here)
here''s
a style recommendation: constants such as Class instances (a.k.a class and 
module definitions or constants that "act" like them) are usually
written
with only the first letter capitalized. Constants of other types (like your 
arrays of strings) are usually ALL_CAPS.

P.P.S. - You may also be interested in the following Ruby syntactic sugar:

TITLE = %w{ ABC DEF GHI JKL }
BODY = %w{ MNO PQR STU VWX }

This of course only works when all the strings in your array are simple and 
don''t contain any whitespace.

-- 
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.

>
> One way to do what you want would be (assuming Title and Body will always 
> contain the same number of elements):
>
>   def posts!
>     Title.each_with_index do |t, i|
>       post! t, Body[i], @current_user.id
>     end
>   end
>  
> I''m sure there are more clever, ruby-ish ways for parallel
iteration that
> using #each_with_index.
>
Okay, I couldn''t help myself. Here''s another
alternative/example for this
kind of "parallel iteration"

fruits = %w{ apples pineapples oranges }
states = %w{ Washington Hawaii Florida }

states.zip(fruits) do |state, fruit|
  puts "#{state} grows #{fruit}"
end 

-- 
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.

>
>   def posts!
>     Title.each_with_index do |t, i|
>       post! t, Body[i], @current_user.id
>     end
>   end
each_for_index is very helpful. Thanks a lot for responses.

-- 
Posted via http://www.ruby-forum.com/.

-- 
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.

On 5 April 2011 21:45, David Kahn
<dk-rfEMNHKVqOwNic7Bib+Ti1W1rNmOCjRP@public.gmane.org>
wrote:
> ...
> does anyone know if there is a way to invoke the
> debugger during rake db:seed or for that matter any other rake task?
rdebug rake whatever

Colin

-- 
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.