saadat

hi,everybody.
I post a mail some days ago,but nobody answer me.again I ask my question,if one knows answer me please.
I am working with orbeon form builder and need to save the name of all countries in database  postgresql ,then make a query and bind the result to a combobox (dropdown),and the user select one name in the combobox.I do not know what I should write in the itemset item , label and how to bind the result of the query to the nodeset......

answer my question as soon as possible,please.I need help.