One-to-many joins with Zend_Db_Table_Select

Let’s say that you want to set up a one-to-many relationship between two tables: Artists and Albums because you’ve refactored my ZF1 tutorial.

Let’s assume that an artist has many albums. These are the basic table definitions:

artists table: id, artist
albums table: id, artist_id, title

When you list the albums, you obviously want to see the artist name rather than the id, so clearly you use a join!

Assuming you’re using Zend_Db_Table, the easiest way is to turn off the integrity check and do a join in a mapper or table method.

Something like this:


class AlbumTable extends Zend_Db_Table_Abstract
{
protected $_name = 'album';

public function fetchAllWithArtistName($order = array('title ASC'))
{
$select = $this->select();
$select->setIntegrityCheck(false);
$select->from($this->_name);

$select->joinLeft('artist', 'album.artist_id = artist.id',
array('artist_name' => 'name'));
$select->order($order);

$rows = $this->fetchAll($select);
return $rows;
}

}

The row set returned will have all the columns from the albums table and one additional column called artist_name which is an alias of the name column from the artists table.

6 thoughts on “One-to-many joins with Zend_Db_Table_Select

  1. It’s worth mentioning that you can do the same query with chaining, if you’re being economic with the keypresses :-)

    $select->from()->where()->order()->limit();

    I love Zend Db, so many people prefer Doctrine though. I’m yet to find a need for it!

  2. You have no idea how long “$select->setIntegrityCheck(false);” evaded me. I all but gave up thinking a join simply wasn’t possible until I found that little snippet.

  3. Well, from a irc chat with @bittarman, he stresses that setIntegrityCheck is – and I quote – “a hack”. It actually returns “broken” row objects. And I agree with him in that you could just use the adapter and get the result set as an array.
    Mind you, I use setIntegrityCheck quite frequently.

  4. First – let’s use some wrinky-ding SQL wrapper ( create a problem for ourselves ) and then heroically overcome it. Mission accomplished.

  5. Yes better just use the db adapter..

    $select = $this->getDefaultAdapter->Select();

    And make the query exactly like you want. And you do not get a fake db table rowset.

  6. Nice, would be cool to see an article on the new Zend_Db that has been cooked up.

    You said that turning off the integrity check is the easiest way… I thought I was about to find out how to do it automatically using the table relationships I defined… still not sure how they’re used or why :D

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