The catalog data element is defined in the xmccat_types_metadata schema as being of this catalogDataType. This allows each domain to defined its own object types in the choice within this type. Defining the type here allows each domain to only need an XML Bean compiled for this xmccat_domain_metadata schema - the same XML Bean can be used for the xmccat types schema for all domains. THE OBJECT TYPES ARE DEFINED FOR EACH DOMAIN AND MUST ALSO BE DEFINED IN THE DATABASE. Each valid root metadata element for a domain should be listed as one of the choices within this type. The any element should be replaced. All of the query response object types based on one or more property filters use this group. The order of metadata properties included is based on the order of the filters in the query. Other than those where the occurrance restriction is unbounded will generally only have a single instance since they occur only once in the schema.