if it is outside a form or other mm data aware container you just instaniate a new object and call the methods you need.
this is vb but you should get the idea.
'the call
Dim myBO as New MyBusinessObject
myBO.Fetch_docbyDLN(1001)
with myBO.entity
do some stuff with entity
endwith


'the BO's fetchmethod
public function Fetch_docbyDLN(byval dln as int64) as entity
me.getdataset("DocbyDLN",me.createparameter("@DLN",dln)
return me.entity
end function