Rails - Jul 2006 - Relationships: one model referencing same table for different data sets?

Hi, 

After I''ve saved, I want to display the Description from the Codes
table that
corresponds with the ID in the Cause table.  

Rails doesn''t seem to like that, because on my form, I have two sets of
data in
combo boxes that come from the Codes table.  So, in the show template, I
can''t
do this:

Cause of Death: <%= @cause.code.description %>

Any ideas?

The database I''m converting from had all the code tables broken out,
but I
wanted to combine them all into one code table.  There must be some way to
display the text instead of the id!!

Any and all help greatly appreciated!

Ali

Lots of ideas, but I''d need to see your migrations / table layouts and
your
models... there''s not enough here to go on.


On 7/13/06, Ali Williams <awilliams@washoecounty.us>
wrote:
>
> Hi,
>
> After I''ve saved, I want to display the Description from the Codes
table
> that
> corresponds with the ID in the Cause table.
>
> Rails doesn''t seem to like that, because on my form, I have two
sets of
> data in
> combo boxes that come from the Codes table.  So, in the show template, I
> can''t
> do this:
>
> Cause of Death: <%= @cause.code.description %>
>
> Any ideas?
>
> The database I''m converting from had all the code tables broken
out, but I
> wanted to combine them all into one code table.  There must be some way to
> display the text instead of the id!!
>
> Any and all help greatly appreciated!
>
> Ali
>
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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Does this help?  Please let me know - I am pulling my hair out over this.  Thank
you!!

class Cause < ActiveRecord::Base 
  has_many :codes   
end

class Code < ActiveRecord::Base
  belongs_to :codetype
  belongs_to :cause  
end

-- 
-- Table structure for table `causes`
-- 

CREATE TABLE `causes` (
  `id` int(11) NOT NULL auto_increment,
  `case_id` int(11) NOT NULL default ''0'',
  `cod_id` int(11) NOT NULL default ''0'',(code.codetype_id
where codetype_id = 4)
  `mod_id` int(11) default ''0'',(code.codetype_id where
codetype_id = 8)
  `cause_texta` varchar(255) default NULL,
  `cause_textb` varchar(120) default NULL,
  `cause_textc` varchar(120) default NULL,
  `cause_textd` varchar(150) default NULL,
  `date_entered` datetime NOT NULL default ''0000-00-00
00:00:00'',
  `entered_by` varchar(15) NOT NULL default '''',
  PRIMARY KEY  (`id`),
  KEY `cod_id` (`cod_id`),
  KEY `case_id` (`case_id`)
) TYPE=MyISAM AUTO_INCREMENT=31 ;

-- 
-- Table structure for table `codes`
-- 

CREATE TABLE `codes` (
  `id` int(11) NOT NULL auto_increment,
  `codetype_id` int(11) NOT NULL default ''0'',
  `abbreviation` varchar(20) default NULL,
  `description` varchar(50) default NULL,
  `other` varchar(35) default NULL,
  `obsolete_date` date default NULL,
  PRIMARY KEY  (`id`),
  KEY `codetype_id` (`codetype_id`)
) TYPE=MyISAM AUTO_INCREMENT=317 ;

Well.. it''s not gonna work because your tables aren''t
following the
conventions.

You have no relationship that Rails can understand in your table
How can I explain this.... What you have here is just not going to work.

If you want a cause to have many codes, then the foreign key needs to be in
the other table... the codes table needs to have the cause_id column.

If you want to have the code_id in the cause table,  it needs to be called
code_id

Then you''d be able to do

class Cause < ActiveRecord::Base
    belongs_to :code
end


Does a cause have multiple codes? If it does, then you need to create a
causes_codes table and use has_and_belongs_to_many

causes_codes
===   cause_id
   code_id



class Cause < ActiveRecord::Base
  has_and_belongs_to_many :codes
end

class Code < ActiveRecord::Base
  belongs_to :codetype
  has_and_belongs_to_many :causes
end

Need more help? let me know.

On 7/14/06, Ali Williams <awilliams@washoecounty.us>
wrote:
>
> Does this help?  Please let me know - I am pulling my hair out over
> this.  Thank
> you!!
>
> class Cause < ActiveRecord::Base
>   has_many :codes
> end
>
> class Code < ActiveRecord::Base
>   belongs_to :codetype
>   belongs_to :cause
> end
>
> --
> -- Table structure for table `causes`
> --
>
> CREATE TABLE `causes` (
>   `id` int(11) NOT NULL auto_increment,
>   `case_id` int(11) NOT NULL default ''0'',
>   `cod_id` int(11) NOT NULL default ''0'',(code.codetype_id
where
> codetype_id = 4)
>   `mod_id` int(11) default ''0'',(code.codetype_id where
codetype_id = 8)
>   `cause_texta` varchar(255) default NULL,
>   `cause_textb` varchar(120) default NULL,
>   `cause_textc` varchar(120) default NULL,
>   `cause_textd` varchar(150) default NULL,
>   `date_entered` datetime NOT NULL default ''0000-00-00
00:00:00'',
>   `entered_by` varchar(15) NOT NULL default '''',
>   PRIMARY KEY  (`id`),
>   KEY `cod_id` (`cod_id`),
>   KEY `case_id` (`case_id`)
> ) TYPE=MyISAM AUTO_INCREMENT=31 ;
>
> --
> -- Table structure for table `codes`
> --
>
> CREATE TABLE `codes` (
>   `id` int(11) NOT NULL auto_increment,
>   `codetype_id` int(11) NOT NULL default ''0'',
>   `abbreviation` varchar(20) default NULL,
>   `description` varchar(50) default NULL,
>   `other` varchar(35) default NULL,
>   `obsolete_date` date default NULL,
>   PRIMARY KEY  (`id`),
>   KEY `codetype_id` (`codetype_id`)
> ) TYPE=MyISAM AUTO_INCREMENT=317 ;
>
>
>
>
>
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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Ok, I get what you''re saying here.  Cause does have multiple codes, BUT
they are
of two different CODE TYPES: cause of death and manner of death.  So what
you''re
saying about adding a code_id to the cause table makes sense, but I''m
working
with two different data sets, so how can I differentiate between the two(cod_id,
mod_id)?  Maybe I need to concede to the fact that my code tables need to be
broken out so I can property conform to what Rails wants.

No that''s easy then


class Cause < ActiveRecord::Base
  belongs_to :cause_of_death, :class_name => "Code", :foreign_key
=>
"cod_id"
  belongs_to :manner_of_death, :class_name => "Code", :foreign_key
=>
"mod_id"
end

@cause = Cause.find :first
@cause.manner_of_death.description
@cause.cause_of_death.description




On 7/14/06, Ali Williams <awilliams@washoecounty.us>
wrote:
>
> Ok, I get what you''re saying here.  Cause does have multiple
codes, BUT
> they are
> of two different CODE TYPES: cause of death and manner of death.  So what
> you''re
> saying about adding a code_id to the cause table makes sense, but
I''m
> working
> with two different data sets, so how can I differentiate between the
> two(cod_id,
> mod_id)?  Maybe I need to concede to the fact that my code tables need to
> be
> broken out so I can property conform to what Rails wants.
>
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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