To automate backend testing we can use database check 
point.during this testing testors r checking the impact of 
frond end operation on backend table in terms of 
verification and validation

First of all we have to know what is back end testing? Back
end testing is nothig but checking the correctness of the 
database. 
With QTP we can write a script which going to connect the 
backend I mean a database of our inquary then we can set it 
on the datatable where we can compare the backend data with 
the real one and determine If there is any inconsistency.
and so on so forth...