DATAMAPPER ORM 1.8.2.1 cascade_delete

[eluser]jx12345[/eluser]
I want to use cascade delete in MySQL, so in application/config/datamapper.php I added the following line:

Code:

$config['cascade_delete'] = FALSE;

This didn't work, but on searching the code base I found line 275 in application/libraries/datamapper.php

Code:

public $cascade_delete = TRUE;

Setting this to FALSE worked but shouldn't this be possible in the config file? or have I misunderstood the documentation

Thanks

Jim