# One to many relationship?

**URL:** <https://www.ruby-forum.com/t/one-to-many-relationship/131670>\
**Category:** Rails\
**Created:** [March 12, 2008, 11:28am UTC](https://www.ruby-forum.com/t/one-to-many-relationship/131670 "2008-03-12T11:28:02Z")\
**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 12, 2008, 11:28am UTC](https://www.ruby-forum.com/t/one-to-many-relationship/131670/1 "2008-03-12T11:28:02Z")

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Hi,

Newbie question (i hope)

2 tables (no rails specs)

CREATE TABLE `werelddelen` (  
`id` smallint(2) unsigned NOT NULL auto\_increment,  
`naam` varchar(50) default NULL,  
`naam_en` varchar(50) default NULL,  
`zoeknaam` varchar(50) default NULL,  
PRIMARY KEY (`id`),  
KEY `zoeknaam` (`zoeknaam`)  
)

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 ‘’,  
`werelddeel_id` tinyint(2) unsigned default NULL COMMENT  
‘wereldelen.id’,  
PRIMARY KEY (`landcode`),  
KEY `land_zoeknaam` (`land_zoeknaam`),  
KEY `werelddeel_id` (`werelddeel_id`)  
)

How can realize a one to many relationship between this tables.(cannot  
change column-names, because this is our central company database)

1)Werelddelen(continents) can have more than 1 land(countries)  
2)Land only can have 1 werelddeel(continent)

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 12, 2008, 11:52am UTC](https://www.ruby-forum.com/t/one-to-many-relationship/131670/2 "2008-03-12T11:52:43Z")

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On 12 Mar 2008, at 10:28, Remco Z. wrote:

> `naam_en` varchar(50) default NULL,  
> `landafk` char(3) default NULL,
> 
> 1)Werelddelen(continents) can have more than 1 land(countries)  
> 2)Land only can have 1 werelddeel(continent)

You want a belongs\_to and a has\_many. You can use the foreign\_key  
option to tell it to use the werelddeel\_id column.

Fred