let xml_of_db = fun db ->
let tables = List.map xml_of_table db.SQL_db.db_tables
and vtables = List.map xml_of_vtable db.SQL_db.db_vtables
and indexes = List.map xml_of_index db.SQL_db.db_indexes
and queries = List.map xml_of_query db.SQL_db.db_queries in
let xml_tables = Xml.Element ("tables", [], tables)
and xml_vtables = Xml.Element ("vtables", [], vtables)
and xml_indexes = Xml.Element ("indexes", [], indexes)
and xml_queries = Xml.Element ("queries", [], queries) in
Xml.Element ("db", [], [xml_tables; xml_vtables; xml_indexes; xml_queries])