Magento Database – Relationship Between customer_entity Table and Sales

If your model extends Mage_Core_Model_Abstract and your resource model is configured correctly you should be able to load the row like this:

$model = Mage::getModel('prefs/prefsemail')->load($id);

Then all your columns should be found in $model->getData()

EDIT
If you want to get data from an other table using a FK try this:

$collection = Mage::getModel('prefs/prefsemail')->getCollection()->addFieldToFilter('fk_name', $fkValue);
foreach ($collection as $item){
    //do something with $item
}

Try it like this:

->addForeignKey(
     $installer->getFkName('namespace_module/shop', 'area_id', 'namespace_module/area','area_id'),
     'area_id',
     $installer->getTable('namespace_module/area'), 
     'area_id',
     Varien_Db_Ddl_Table::ACTION_CASCADE, 
     Varien_Db_Ddl_Table::ACTION_CASCADE
)  

The difference in my code is that I removed the first line below getFkName.
since you are calling addForeignKey on a table while creating it, you don't need to specify it's name again.

as a general rule use:

->addForeignKey(
     $installer->getFkName('TABLE ALIAS', 'FK_FIELD', 'REF_TABLE_ALIAS','REF_TABLE_FIELD'),
     'CURRENT_TABLE_FIELD_NAME',
     $installer->getTable('REF_TABLE_ALIAS'), 
     'REF_TABLE_FIELD',
     Varien_Db_Ddl_Table::ACTION_CASCADE, 
     Varien_Db_Ddl_Table::ACTION_CASCADE
)  

[Edit]
You should be looking at Varien_Db_Ddl_Table::addForeignKey because you are using it on an instance of Varien_Db_Ddl_Table.