2. The method of claim 1 , wherein the SQL statement selects data only from the particular column of the particular relational table.
2. The method of claim 1 , wherein the SQL statement selects data only from the particular column of the particular relational table. 5. The method of claim 2 , further comprising performing operations on the target data after retrieving the target data, wherein the operations on the target data are performed by the relational database system receiving a second Xpath expression and converting the second Xpath expression into a second SQL statement.