A database server registers an XML schema and determines a database representation for the XML schema and mapping information, determining what database types should be used to represent an XML schema and/or how instances of the XML schema are stored by a database system. The mapping information indicates the mapping between the constructs declared in the XML schema and the constructs included in the appropriate database representation. The XML schema may contain annotations that describe one or more properties of a database representation of an XML date-time type. Based on the annotations, the database determines an appropriate database representation and generates mapping information mapping the declaration of the XML date-time type of the XML schema to the constructs of the database representation.