I have developed a custom module which includes three DB tables. I need to fetch values from one table and then based on that value fetch values from second table.

For ex below is the table description:

`**deal_offers**  : entity_id | deal_name | deal_discount`

`**deal_products** : deal_id | product_id`

In my observer, I am getting `product_id` value. Now for say `product_id`, what I want to achieve is 

 1. First, fetch `deal_id` value from table `deal_products`, using the value
    of product_id

 2. Next, fetch `deal_discount` value, using `deal_id` which is the
    **entity_id** in table `deal_offers`

I have defined `<entities>` in my config.xml for these two tables, but not getting success 
in achieving the desired result using `Mage::getModel('module/model')` method in my observer. 


Please Help

Thanks
Thanks