update work order using sql

hi i am making a application that will handle work orders. and i need a way to commit a item in a work order and some times even change the price.

so first i was thinking that i can just do a simple update like this

Update OrderEntry Set QuantityOnOrder = 0,QuantityRTD = 1,Price = 12.99,Taxable = 1 Where ID = 20144

but my question is what else needs to be updated? 

i want the inventory to update, and the customers balance to update, and everything that would of updated when i do it trough RMS

is there a documentation on how to do such things?

and if sql updates is not the way, but rather some kind of add-on or a dot net dll that can do it, where do i find that