Question

Basically, I want to build the relation between the tables ‘cities’ and ‘images’. They both have an ID column which is constrained by a third table called cities_images. Here’s the structure of the table in the middle:

CREATE TABLE IF NOT EXISTS `cities_images` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `cityId` int(11) NOT NULL,
  `imageId` int(11) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `imageId` (`imageId`),
  KEY `cities_images_ibfk_2` (`cityId`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ;

ALTER TABLE `cities_images`
  ADD CONSTRAINT `cities_images_ibfk_2` FOREIGN KEY (`cityId`) REFERENCES `cities` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
  ADD CONSTRAINT `cities_images_ibfk_1` FOREIGN KEY (`imageId`) REFERENCES `images` (`id`) ON DELETE CASCADE ON UPDATE CASCADE

I have two models that work with the cities and images tables.

Relation inside Cities.php:

'citiesImages' => array(self::MANY_MANY, 'CitiesImages', 'cities_images(id,cityId)'),

Relation inside Images.php:

'citiesImages' => array(self::MANY_MANY, 'CitiesImages', 'cities_images(id,imageId)'),

I am trying a test action inside CitiesController with the following content:

$cities = Cities::model()->findByPk(2);
var_dump($cities->images);exit;

But this results in an error:

Property “Cities.images” is not defined.

Note that there is a city with ID=2 and there is a row in cities_images with cityId=2 and imageId=1. There is also a row in the images table with ID=1, so I don’t see why I can’t access the images associated with the given City.

Answer 1

You are just referencing the wrong name. Should be:

$cities = Cities::model()->findByPk(2);
var_dump($cities->citiesImages);exit;

Because that is how it is setup in the Cities.php model.

UPDATE:

Right, you need to simply change the models to point to the right model:

Cities.php:

'citiesImages' => array(self::MANY_MANY, 'Images', 'cities_images(imageId,cityId)'),

Images.php:

'citiesImages' => array(self::MANY_MANY, 'Cities', 'cities_images(cityId,imageId)'),