Read the XML and insert into SQL Table using stored procedur

Question

Read the XML and insert into SQL Table using stored procedure If record already exist than do not insert - Only through Stored Procedure


My Query :-  In this query it works only If the entire XML is parsed again, than it will not insert duplicate records , But If you change the 1 record out of 3 records in XML than it will insert all there records again, that means again duplicate records in table, Could any one please help me how can I avoid this problem.
looks like I need to traverse each records in XML using curser or forloop, please help me