Hi everyone,
I was wondering what the prefered way is of dealing with inheritance structures in models.
for example may have a site the administrates videos and pictures. both would extend from content items.
in ContentItem I would store width, height and filesize as these attributes are common to both types. A video would for exapmle also have duration implemented.
Is there a way to implement class table or single table inheritance with Yii?
thanks
Marc
I don't understand what you're going to approach, but you can do something like this with your models:
POJO (Plain Old Java Objects) by extending CActiveRecord.
ContentItem class:
<?php
class ContentItem extends CActiveRecord
{
public static function model($className=__CLASS__)
{
return parent::model($className);
}
public function tableName()
{
return 'contentItems';
}
public function rules()
{
return array(); //replace with what the class needs to be validated
}
public function relations()
{
return array(
'videos' => array(self::HAS_MANY, 'Video', 'contentItemId'),
'photos' => array(self::HAS_MANY, 'Photo', 'contentItemId')
);
}
}
Video class:
<?php
class Video extends CActiveRecord
{
public static function model($className=__CLASS__)
{
return parent::model($className);
}
public function tableName()
{
return 'videos';
}
public function rules()
{
return array(); //replace with what the class needs to be validated
}
public function relations()
{
return array(
'contentItems' => array(self::BELONGS_TO, 'ContentItem', 'contentItemId')
);
}
}
Photo class:
<?php
class Photo extends CActiveRecord
{
public static function model($className=__CLASS__)
{
return parent::model($className);
}
public function tableName()
{
return 'photos';
}
public function rules()
{
return array(); //replace with what the class needs to be validated
}
public function relations()
{
return array(
'contentItems' => array(self::BELONGS_TO, 'ContentItem', 'contentItemId')
);
}
}
The Manager Classes is where you actually do your structure models:
ContentManager class:
<?php
class ContentManager
{
public function createAction(ContentItem $contentItem)
{
$contentItem->save();
}
public function updateAction(ContentItem $contentItem)
{
$contentItem->update();
}
public function deleteAction(ContentItem $contentItem)
{
$contentItem->delete();
}
public function getContent($id)
{
return ContentItem::model()->findByPk($id);
}
}
VideoManager class:
<?php
class VideoManager extends ContentManager
{
public function createAction(ContentItem $contentItem, Video $video)
{
$transaction = $contentItem->dbConnection->beginTransaction();
try {
$contentItem->save();
$video->save();
$transaction->commit();
} catch (Exception $e)
{
echo '<p>'.$e->getMessage().'</p>';
$transaction->rollback();
}
}
public function updateAction(ContentItem $contentItem, Video $video)
{
$transaction = $contentItem->dbConnection->beginTransaction();
try {
$contentItem->update();
$video->update();
$transaction->commit();
} catch (Exception $e)
{
echo '<p>'.$e->getMessage().'</p>';
$transaction->rollback();
}
}
public function deleteAction(ContentItem $contentItem, Video $video)
{
$contentItem->delete();
$video->delete();
}
public function getVideos($id)
{
$video= ContentItem::model()->with('videos', 'videos.duration')->findByPk($id);
}
}
Also for the PhotoManager would be the same like VideoManager. I have not tested those just a quick scratchy codes.
thanks for your reply.
What I was actually looking for was something like single table inheritance which is described here
http://www.martinfow…nheritance.html
In my case I'd basically have one table called content_items which has a type column that is either video or picture.
The table would have to columns id, type, width, height, filesize, duration
for pictures duration would stay NULL.
I would then have the classes Video and Picture which are both subclasses of ContentItem.
ContentItem would have their shared functions and then I can overwrite or add some functions in the two subclasses.
When I do Picture::model()->findAll(); it should access the content items table and automatically add the type = 'picture' condition.
Similarily when calling $picture->save() the type attribute shuold be set automatically.
CakePHP, Ruby on Rails and I believe Kohana have built in behaviours to implement single table inheritance or class table inheritance which is described here
http://www.martinfow…nheritance.html
I was looking for something similar in Yii since my application has a number of inherited models
Right now the only support is the instantiate() method in AR which you can override to create concrete child class instance when calling find() method. You will also need to override beforeSave() method to set the "type" column. We plan to improve the support for this in 1.1 release.
thanks for your answer qiang
I'm looking forward to 1.1