Create Query on Data table output.

hi All,
     In my project i having one XML its includes around 10 tables [ when we using dataset.,ReadXML can see 10 table] ,these tables are related with each other,so i need to get the data from these tables using query but i dont have any SQL Db or other.
is there any way to solve this problm?
Thanks 
SUJILKUMAR
...