Difference between light SetDirection and SetPosition/Rotati

what is the difference between when i set light rotation and direction ?
is the light setDirection is the end target for which the the light is pointing at ?
so i don’t need to set the rotation ?

SetDirection() and SetRotation() are just different ways of achieving the same thing: setting the scene node’s orientation in space. The light always shines in the direction of its scene node’s local forward (positive Z) axis.

Thanks for your quick answer