问题
I am new to zend. I have been asked to redevelop a website that was once written in plain PHP and put it into the zend framework.
I am having a lot of trouble with database relationships, I cant seem to get my head round defining and querying relationships.
I would like to find a Category. From that Category I would like to be able to find all the CategoryInfo associated with it, and be able to query/sort/limit that dataset.
Here are my models.
Categorys.php
<?php
class Default_Model_Categorys extends Zend_Db_Table_Abstract
{
protected $_name = 'Categorys';
protected $_primary = 'id';
protected $_dependentTables = array('Default_Model_CategoryInfo');
}
?>
CategoryInfo.php
<?php
class Default_Model_CategoryInfo extends Zend_Db_Table_Abstract
{
protected $_name = 'Category_Info';
protected $_primary = 'id';
protected $_referenceMap = array(
'Categorys' => array(
'columns' => array('cat_id'),
'refTableClass' => 'Default_Model_Categorys',
'refColumns' => array('id')
)
);
}
?>
CategoryController.php
<?php
class CategorysController extends Zend_Controller_Action
{
public function indexAction()
{
/*
this should redirect to all games
*/
return $this->_forward("index", "games");
}
public function categoryAction()
{
/*
shows a specific category
*/
$id = (int) $this->_request->getParam('id');
$category = new Default_Model_Categorys();
$this->view->category = $category->fetchRow(
$category->select()->where('id = ?', $id)
);
$categoryInfo = $this->view->category->findDependentRowset('Default_Model_CategoryInfo');
}
}
Firstly... am I doing anything wrong?
Secondly... how do I go about querying the dependent rowset?
回答1:
First, if you're searching for a category by its primary key, it's simpler to use the find()
method:
$id = (int) $this->_request->getParam('id');
$category = new Default_Model_Categorys();
$this->view->category = $category->find($id)->current();
Second, to restrict or sort dependent Category_Info
rows, you can use a Zend_Db_Table_Select
object as an optional parameter of findDependentRowset()
. Here's an example:
$select = $category->select()->where("info_type = 'PRICE'")
->order("info_date")
->limit(3);
$categoryInfo = $this->view->category->findDependentRowset(
'Default_Model_CategoryInfo', null, $select);
Notice you can use any table object to create that select object. Since the "FROM
" clause for that select will be set by the findDependentRowset()
method, you just add other clauses and then pass it in.
PS: You don't need to declare $_dependentTables
at all, unless you're going to use cascading update or cascading delete via PHP code. I recommend strongly against doing that -- it's far more efficient to let the RDBMS handle those cascading operations.
Likewise you should never have to declare $_primary
if your database tables actually declare primary key constraints. Zend_Db_Table_Abstract
knows how to inspect metadata to get the primary key column(s).
回答2:
Everything looks correctly to me. You don't query a dependent rowset. It is a query itself and it returns a result set. Basically what it is doing is pulling all records related to the current row you are working with as defined by $_referenceMap. Once you execute findDependentRowset(), you can foreach over the results which will give you instances of Zend_Db_Table_Row. From there you can display the related data as needed.
Personally I don't use Zend_Db Relationships. It is much easier to just make a second model method to query what I need. Also, Zend_Db Relationships do not support where clauses, so just making a second query is much more flexible than relationships.
来源:https://stackoverflow.com/questions/1454705/zend-relationships-with-select