Rails - Apr 2005 - Handling Multiple Categories for Articles

Hi, 
    New to Rails here and I''m trying to determine the correct method to
add a ''Post''  to multiple ''categories''.

   I have a select list that allows you to select multiple categories to 
store your post in, it translates into
{"category"=>{"id"=>["1", "3"]}

   I have the relations set up in my model:

class Post < ActiveRecord::Base
  has_and_belongs_to_many :categories, :join_table =>
"map_category_post"
  belongs_to :user
 
end

  What I''m confused about is how to save this to the database?

   def create
      @post = Post.new(@params[:post])
      #I''ve tried a few things here, but was unsuccessful.
    if @post.save
      flash[''notice''] = ''Post was successfully
created.''
      redirect_to :action => ''list''
    else
      render_action ''new''
    end
  end


 Many thanks,
     -Justin

Justin wrote:
> Hi,    New to Rails here and I''m trying to determine the correct
method
> to add a ''Post''  to multiple
''categories''.
> 
>   I have a select list that allows you to select multiple categories to 
> store your post in, it translates into
{"category"=>{"id"=>["1", "3"]}
> 
>   I have the relations set up in my model:
> 
> class Post < ActiveRecord::Base
>  has_and_belongs_to_many :categories, :join_table =>
"map_category_post"
>  belongs_to :user
> 
> end
> 
>  What I''m confused about is how to save this to the database?
This ought to do it:
>   def create
>      @post = Post.new(@params[:post])
>      #I''ve tried a few things here, but was unsuccessful.
      @post.categories.clear
      @params["category"]["id"].each do |id|
        @post.categories << Category.find(id)
      end
>    if @post.save
>      flash[''notice''] = ''Post was successfully
created.''
>      redirect_to :action => ''list''
>    else
>      render_action ''new''
>    end
>  end

Look at the examples in the ACL controller example here:

http://wiki.rubyonrails.com/rails/show/AccessControlListExample

It does a good job of explaininng.  

My guess is something like this though:

def create
  @post = Post.new(@params[''post''])
  categories =
@params[''post''][''categories''][''id'']
  categories.each do |category|
    @category = Category.find(id)
    @post.categories<<@category
  end
  if @post.save
    flash[''notice''] = ''Post was successfully
created''
    redirect_to :action => ''list''
  else 
    render_action ''new''
  end
end

You didn''t say if the categories needed to be created if the 
don''t exist.  But this should be close.

jim


On Fri, 2005-04-15 at 20:40 -0500, Justin wrote:
> Hi, 
>     New to Rails here and I''m trying to determine the correct
method to
> add a ''Post''  to multiple ''categories''.
> 
>    I have a select list that allows you to select multiple categories to 
> store your post in, it translates into
{"category"=>{"id"=>["1", "3"]}
> 
>    I have the relations set up in my model:
> 
> class Post < ActiveRecord::Base
>   has_and_belongs_to_many :categories, :join_table =>
"map_category_post"
>   belongs_to :user
>  
> end
> 
>   What I''m confused about is how to save this to the database?
> 
>    def create
>       @post = Post.new(@params[:post])
>       #I''ve tried a few things here, but was unsuccessful.
>     if @post.save
>       flash[''notice''] = ''Post was successfully
created.''
>       redirect_to :action => ''list''
>     else
>       render_action ''new''
>     end
>   end
> 
> 
>  Many thanks,
>      -Justin
> 
> 
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
-- 
Jim Ray
<jim-rhf1kIDhBaeB8E1WFlbJj6xOck334EZe@public.gmane.org>

Or even:

def create
   @post = Post.new(@params[:post])

   if @dj.save
     @dj.posts << Category.find(@params[''category''])
     flash[''notice''] = ''New post saved.''
     redirect_to :action => ''list''
   else
     # Tell user the save failed.
   end
end

-- 
Regards, Charles.

Total Rails newbie here;

I have a table named `blog_categories` and am trying to create scaffold code
via:
> ruby script\generate scaffold BlogCategory
and am getting this error:

error  Before updating scaffolding from new DB schema, try creating a tab
le for your model (BlogCategory)

I''ve also tried:
> ruby script\generate scaffold BlogCategories
> ruby script\generate scaffold Blog_Category
And always get similar errors.  Any tips?  Is there a comprehensive guide to
naming conventions for ActiveRecord?  Most of the tutorials I''ve seen
describe
single-word table names which hasn''t helped me out.

Thanks

Mike Evans <mike-u4reGlrcmwqg/H9aKuUo6lBd07bTekyB@public.gmane.org>
writes:
> error  Before updating scaffolding from new DB schema, try creating a tab
> le for your model (BlogCategory)
Are you certain the blog_categories table exists in the database
defined in config/database.yml and that it has a scheme?  Can you show
the scheme here?
-- 
doug-jGAhs73c5XxeoWH0uzbU5w@public.gmane.org

Quoting Doug Alcorn <doug-jGAhs73c5XxeoWH0uzbU5w@public.gmane.org>:
> Mike Evans <mike-u4reGlrcmwqg/H9aKuUo6lBd07bTekyB@public.gmane.org>
writes:
>
>> error  Before updating scaffolding from new DB schema, try creating a
tab
>> le for your model (BlogCategory)
>
> Are you certain the blog_categories table exists in the database
> defined in config/database.yml and that it has a scheme?  Can you show
> the scheme here?
> --
Yes, I triple checked... here''s the table:

DROP TABLE IF EXISTS `blog_categories`;
CREATE TABLE `blog_categories` (
  `id` smallint(5) unsigned NOT NULL auto_increment,
  `category` varchar(20) NOT NULL default '''',
  `created_on` timestamp NOT NULL default CURRENT_TIMESTAMP on update
CURRENT_TIMESTAMP,
  `updated_on` timestamp NOT NULL default ''0000-00-00
00:00:00'',
  PRIMARY KEY  (`id`),
  UNIQUE KEY `category_key` (`category`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COMMENT=''List of
categories''
AUTO_INCREMENT=6 ;

Does it matter which form I use?:
> ruby script\generate scaffold BlogCategories
> ruby script\generate scaffold BlogCategory

> Does it matter which form I use?:
> > ruby script\generate scaffold BlogCategories
> > ruby script\generate scaffold BlogCategory
You should use singular for model names, and plural (with underscores)
for table names.

Thus... BlogCategory -> blog_categories

Tomas

Ok, that makes sense.  But any idea why I keep getting this?:
error  Before updating scaffolding from new DB schema, try creating a tab
le for your model (BlogCategory)

When I do have a table called `blog_categories`?

Quoting Tomas Jogin <tomasj-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>:
>> Does it matter which form I use?:
>> > ruby script\generate scaffold BlogCategories
>> > ruby script\generate scaffold BlogCategory
>
> You should use singular for model names, and plural (with underscores)
> for table names.
>
> Thus... BlogCategory -> blog_categories
>
> Tomas
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

> When I do have a table called `blog_categories`?
When you have a model called BlogCategory.

Regards,
Tomas
> > You should use singular for model names, and plural (with underscores)
> > for table names.
> >
> > Thus... BlogCategory -> blog_categories
> >

Tomas Jogin <tomasj-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> writes:
>> When I do have a table called `blog_categories`?
>
> When you have a model called BlogCategory.
We keep dancing around his problem.  He claims he has (and has posted
the scheme for) a blog_categories table.  He also claims he has a
model called BlogCategory.  He''s still getting an error when he
generates the scaffolding complaining there''s no scheme for the
table.  You can scroll back up through this tread to see the details
of the error.  Assuming what he has said is true, I don''t know why the
scaffold generator would give that error.
-- 
doug-jGAhs73c5XxeoWH0uzbU5w@public.gmane.org

So sorry, I misread him. He wrote "When I do...?", but I read it as
"When do I...?"

Tomas

On 4/20/05, Doug Alcorn <doug-jGAhs73c5XxeoWH0uzbU5w@public.gmane.org>
wrote:
> Tomas Jogin <tomasj-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> writes:
> 
> >> When I do have a table called `blog_categories`?
> >
> > When you have a model called BlogCategory.
> 
> We keep dancing around his problem.  He claims he has (and has posted
> the scheme for) a blog_categories table.  He also claims he has a
> model called BlogCategory.  He''s still getting an error when he
> generates the scaffolding complaining there''s no scheme for the
> table.  You can scroll back up through this tread to see the details
> of the error.  Assuming what he has said is true, I don''t know why
the
> scaffold generator would give that error.
> --
> doug-jGAhs73c5XxeoWH0uzbU5w@public.gmane.org
>

On 19/04/2005, at 10:32 PM, Mike Evans wrote:
> I have a table named `blog_categories` and am trying to create 
> scaffold code
> via:
>> ruby script\generate scaffold BlogCategory
> and am getting this error:
>
> error  Before updating scaffolding from new DB schema, try creating a 
> tab
> le for your model (BlogCategory)
Have you checked your db settings etc?
Is the table in correct db, _development and not _test?
Have you been sucessful generating scaffold for other tables?
Have you tried deleting and recreating the said table?

If none of the above helps, add the -t option to the scaffold command 
to get a backtrace, and post that here too.

- tim lucas

Sorry about all the confusion ;-)

Well, everyone is right, I''ve narrowed the problem down to the db 
connection. in my database.yml:

development:
  adapter: mysql
  database: mike_blog
  host: dev.arl.arizona.edu
  username: mike
  password: *******

It doesn''t matter what database name I give (including the right one, 
that does
contain the right table)... I get the same error, but if I change the
connection (host, username, password) parameters, I get a different db
connection error.

So, there''s got to be something wrong here.  I''m going to try
installing rails
on another machine and try running some tests, but if someone has an idea,
please chime in.



Quoting Tim Lucas <t.lucas-l/qNJNvq70OzaBltdDZI6w@public.gmane.org>:
> On 19/04/2005, at 10:32 PM, Mike Evans wrote:
>> I have a table named `blog_categories` and am trying to create scaffold
code
>> via:
>>> ruby script\generate scaffold BlogCategory
>> and am getting this error:
>>
>> error  Before updating scaffolding from new DB schema, try creating a
tab
>> le for your model (BlogCategory)
>
> Have you checked your db settings etc?
> Is the table in correct db, _development and not _test?
> Have you been sucessful generating scaffold for other tables?
> Have you tried deleting and recreating the said table?
>
> If none of the above helps, add the -t option to the scaffold command 
> to get a backtrace, and post that here too.
>
> - tim lucas
>
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Mike Evans <mike-u4reGlrcmwqg/H9aKuUo6lBd07bTekyB@public.gmane.org>
writes:
>  host: dev.arl.arizona.edu
To make things simple, you might try running rails on the host where
mysql is.  In other words, run rails on localhost.
-- 
doug-jGAhs73c5XxeoWH0uzbU5w@public.gmane.org