# Define relationschip external database-scheme

**URL:** <https://www.ruby-forum.com/t/define-relationschip-external-database-scheme/131126>\
**Category:** Ruby\
**Created:** [March 6, 2008, 9:04am UTC](https://www.ruby-forum.com/t/define-relationschip-external-database-scheme/131126 "2008-03-06T09:04:26Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![remco123](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/779978/32.png) [@remco123](https://www.ruby-forum.com/u/remco123)\
**Post date:** [March 6, 2008, 9:04am UTC](https://www.ruby-forum.com/t/define-relationschip-external-database-scheme/131126/1 "2008-03-06T09:04:26Z")

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Hi,

i want to use or external database for my rails app. The connention to  
the external database(no-rais-app) works fine, but how must i define the  
relationship between this tabels (if possibly no change in the table  
scructure)

The external database-scheme:

CREATE TABLE `bestemmingen` (  
`bestemming_id` char(3) NOT NULL default ‘’,  
`naam` varchar(50) default NULL,  
`naam_en` varchar(50) default NULL,  
`landcode` char(2) default NULL,  
`airport_name` varchar(100) default NULL,  
`alt_naam` varchar(50) default NULL,  
`dist_ams` decimal(6,1) default NULL,  
`stad_zoeknaam` varchar(50) NOT NULL default ‘’,  
PRIMARY KEY (`bestemming_id`),  
KEY `land_id` (`landcode`),  
KEY `stad_zoeknaam` (`stad_zoeknaam`)  
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COMMENT=‘Bestemming iatacode en  
iso bestand’;

CREATE TABLE `landen` (  
`landcode` char(2) NOT NULL default ‘’,  
`naam` varchar(50) NOT NULL,  
`naam_en` varchar(50) NOT NULL,  
`alt_naam` varchar(200) NOT NULL,  
`landafk` char(3) default NULL,  
`land_zoeknaam` varchar(100) NOT NULL default ‘’,  
PRIMARY KEY (`landcode`),  
KEY `land_zoeknaam` (`land_zoeknaam`)  
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COMMENT=‘Landen opzoek tabel’;

Grtz…remco

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<div class="post-metadata">

**Author:** ![remco123](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/779978/32.png) [@remco123](https://www.ruby-forum.com/u/remco123)\
**Post date:** [March 6, 2008, 10:39am UTC](https://www.ruby-forum.com/t/define-relationschip-external-database-scheme/131126/2 "2008-03-06T10:39:41Z")

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On Thu, Mar 6, 2008 at 9:04 AM, Remco Z. wrote:

> `bestemming_id` char(3) NOT NULL default ‘’,  
> ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COMMENT='Bestemming iatacode en  
> KEY `land_zoeknaam` (`land_zoeknaam`)  
> ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COMMENT=‘Landen opzoek tabel’;

(excuse my lack of Dutch 😉

class Land \< ActiveRecord::Base  
set\_table\_name “landen”  
has\_many :bestemmingen, :class\_name =\> “Bestemming” # land\_id will be  
guessed  
end

class Bestemming \< ActiveRecord::Base  
set\_table\_name “bestemmingen”  
belongs\_to: :land # land\_id will be guessed  
end

Note: Next time try to ask directly on rails google group, you’ll get  
much better answer there.  
Note 2:I haven’t worked with rails for a long time, so take this as a  
direction, not ready code.  
Note 3:You can find all this on [api.rubyonrails.com](http://api.rubyonrails.com), in the part about  
ActiveRecord.

Jano