12. The medium of claim 10 , wherein: determining that said XML schema defines a cyclic construct includes detecting that an ascendant element and a descendant element that descends from the ascendant element are involved in said cyclic construct; the database representation includes an out-of-line table for storing said ascendant element; and generating a mapping includes generating a mapping that maps said ascendant element to said out-of-line table.
14. The medium of claim 12 , wherein: said descendant element and said ascendant element are mapped to an object type; said out-of-line table is defined by said database server to store objects of said object type; and said object type defines a reference for referring to an object within said out-of-line table.