# Relating tables from different datbases possibly?

**URL:** <https://www.ruby-forum.com/t/relating-tables-from-different-datbases-possibly/131472>\
**Category:** Rails\
**Created:** [March 10, 2008, 1:50pm UTC](https://www.ruby-forum.com/t/relating-tables-from-different-datbases-possibly/131472 "2008-03-10T13:50:10Z")\
**Posts on this page:** 1\
**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 10, 2008, 1:50pm UTC](https://www.ruby-forum.com/t/relating-tables-from-different-datbases-possibly/131472/1 "2008-03-10T13:50:10Z")

</div>

Hi,

Has an external table wich i connect through this code. So the table  
“bestemming” is stored on the exterbal database fly2.

class External \< ActiveRecord::Base  
establish\_connection :extern  
self.abstract\_class = true  
end

class Bestemming \< External  
has\_and\_belongs\_to\_many :tags  
belongs\_to :land, :foreign\_key =\> “landcode”  
set\_table\_name “bestemmingen”  
set\_primary\_key “bestemming\_id”  
end

On my rails app database fly1 i added to 2 tables for tagging.

CREATE TABLE `tags` (  
`id` int(11) NOT NULL auto\_increment,  
`name` varchar(100) NOT NULL default ‘’,  
PRIMARY KEY (`id`)  
)

CREATE TABLE `expenses_tags` (  
`bestemming_id` int(11) NOT NULL default ‘0’,  
`tag_id` int(11) NOT NULL default ‘0’  
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

1)the relating table is in alphabetical order bestemming\_tags  
2)the field relating to a tag’s id is tag\_id  
3)the field relating to an bestemming’s id is bestemming\_id(database  
fly)

I added some tag-list code in my editing-form for bestemming. I got this  
error.

Mysql::Error: Table ‘fly2.bestemmings\_tags’ doesn’t exist: SHOW FIELDS  
FROM bestemmings\_tags

I goes to the wrong database!!!

Help wanted please