8. The method of claim 1 , wherein said complex type is an opaque type.
8. The method of claim 1 , wherein said complex type is an opaque type. 9. The method of claim 8 , wherein: converting said instance of said complex type includes invoking a user registered function registered to convert instances of said complex type to logical representations of said instances; and converting said logical representation to said second storage format includes invoking a user registered function registered to convert logical representations of instances of said complex type to said second storage format.