CakePHP linking a hasMany relationship with a different index - php

Question

I have a table of securities like so:
CREATE TABLE IF NOT EXISTS `securities` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`ticker` varchar(36) NOT NULL,
`name` varchar(180) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ticker` (`ticker`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=585 ;
I.e. the primary key is id whilst there is another unique index ticker.
The ticker index refers to my other table, secuity_prices which has this
CREATE TABLE IF NOT EXISTS `security_prices` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`price_date` date NOT NULL,
`ticker` varchar(36) NOT NULL,
`price` decimal(10,6) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=88340 ;
I want to define a hasMany relationship between them such that security hasMany securityPrice [securityPrice belongsTo security].
The problem I am having is that Cake is using the primary key of security to link to the security_prices table instead of the ticker field. How can I get the join to be made via the ticker?
Here are my relationships:
//Security
public $hasMany = array(
'SecurityPrice' => array(
'className' => 'SecurityPrice',
'foreignKey' => 'ticker',
)
);
//SecurityPrice
public $belongsTo = array(
'Security' =>
array(
'className' => 'Security',
'foreignKey' => 'ticker',
)
);

Answer 1

You can't use $hasMany to do this, because those associations require that you follow Cake's naming conventions for the primary key. You are trying to join two tables via non-primary key columns. That can be done, but not via Cake's automatic associations.
You need to add the join conditions when performing a find operation or pagination operation.
http://book.cakephp.org/2.0/en/models/associations-linking-models-together.html#joining-tables
$options['joins'] = array(
array('table' => 'security_prices',
'alias' => 'SecurityPrice',
'type' => 'LEFT',
'conditions' => array(
'Security.ticker = SecurityPrice.ticker',
)
)
);
$Security->find('all', $options);
If you have to do this often, then you should create a custom find type.
http://book.cakephp.org/2.0/en/models/retrieving-your-data.html#creating-custom-find-types
class Security extends AppModel {
public $findMethods = array('ticker' => true);
protected function _findTicker($state, $query, $results = array()) {
if ($state === 'before') {
$query['joins'][] = array(
array('table' => 'security_prices',
'alias' => 'SecurityPrice',
'type' => 'LEFT',
'conditions' => array(
'Security.ticker = SecurityPrice.ticker',
)
)
);
return $query;
}
return $results;
}
}
Then later it's easy to find with the join.
$Security->find('ticker',.....);