till now i didn’t ise this method but,i know that
In update() values stored in buffer then update the record with reference to RecID & doupdate() can directly update the record with out cheking the condisions and all.
if we want to select particular record with some conditons…then we use update() method.but In some situation we didn’t need to chek the condition,in that situation we use DoUpdate().
I don’t know how useful this information & am not sure this is exact process…cause am also new to DAX.