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Suppose I have a simple Model A that target table A now I have to add some extra info so I decide to create a Model B and save those extra info in a Table B with a foreign key pointing to Table A index key.

Usually Join are done in collections but if I load a model the collection is not called, instead only the resource model is used.

How can I can modify Model A to load also data from Table B on load() ?

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Good Question...I like it – Amit Bera Jul 8 '14 at 11:54
It is a kind of EAV simple implementation ... I found a kind of solution but I'm waiting for other approach and test it, before posting it – Fra Jul 8 '14 at 12:00
up vote 6 down vote accepted

Inside resource model class add following function

protected function _getLoadSelect($field, $value, $object)
    $select = parent::_getLoadSelect($field, $value, $object);

        array('t_b' => 'table_b'),
        $this->getMainTable() . '.id =',
    return $select;

When you called Mage::getModel('modulename/TableA')->load(1), this method will join with table_b.

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I think limit(1) is not required:joinLeft() will be enough ... – Fra Jul 8 '14 at 14:37
I just set an example for that. You can change this according to your requirement. – Sohel Rana Jul 8 '14 at 15:07

I can propose you the approach that I use, and it is quite easy.


  1. Rewrite resource model of Model A (If Model A is yours model and not Magento then you can skip this step)

  2. Rewrite method _getLoadSelect() of resource model of Model A. Select query is generated in this method and here you can join your the other tables.

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You beat me to it. +1 – Marius Jul 8 '14 at 12:24
+1 for the correct workflow infos – Fra Jul 8 '14 at 15:56

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