UBIF Schema Supplementary Report

(Version: SDD 1.0 beta 2 - with UBIF 1.0 beta 18 - !Simplified single file version!)

TDWG working group: Structure of Descriptive Data (SDD)

The standard schema reports generated by xml spy or the xs3p script document the structure of the schema organized by the element and type tree. As a supplement to this, this report documents the use of selected features throughout the entire schema.

This is a highly technical report aimed at xml schema experts. The purpose of the type and element listing is primarily to search for design problems or errors in the schema. The overview over default values and identity constraints is valuable for implementers.

Table of contents

1. Table of elements (name/type synopsis)
2. Table of defined default values
3. Type usage
   • Usage of complex types
   • Usage of simple types
   • Summary of types present but not used
   • Recursive use of types
4. Type inheritance
   • Complex types derived by extension
   • Complex types derived by restriction
   • Simple types derived by restriction
5. Table of annotations containing the problem marker (= '@')

Table of elements (name/type synopsis)

The SDD schema uses element names with different types, depending on the context. To write xslt it is often useful to know which element names in a schema uniquely identify a type, and where the content type depends on the context. The following list shows all elements in alphabetical order together with their type name. Anonymous types, including anonymous type derivations, are annotated with "(anon.)". An advanced script may list the base type of a derivation, but in most cases we avoid anonymous derivation in the TDWG schemata so we did not implement this yet. In the context column the path to the element is given. Elements names are shown directly, and complex type and element/attribute group names are prefixed with "type:", "group:", and "attgroup:", respectively.

The use of an element name with several different types has two major sources: a) the alternative element types are themselves all derived from a base type (see e. g. Modifiers), or b) an object is defined in one place and a reference is made to it. This is very similar to the usage pattern in xml schema itself, where object names are used both for definition and reference (examples: element name="x" and element ref="x", or group name="y" and group ref="y").

Note: element names starting with underscore (= tentative elements placed for the purpose of discussion) are not shown.

Table of defined default values

Elements or attributes for which default values have been defined in the schema need special attention insofar as the processing of an instance document depends on whether it has been validated against the schema (validation will add default values in the infoset). A script or application processing instance documents may thus either validate the document, or it may handle the following attributes itself.

Type usage

The following tables provide an overview of the number of times complex and simple types are used in the schema. Only schema-specific types are reported, not the w3c defined base types (xs:string, xs:boolean, etc.). Type usage is interesting to detect orphan (unused) types, or to argue whether types used only a single time should rather be anonymous.

Usage of complex types

Usage of simple types

Summary of types present but not used

The following types have been defined in the schema, but are not used in elements, attributes, extension, or restriction:
Complex types:
(none)
Simple types:
(none)

Recursive use of types

Direct recursion: The following complex types contain elements of their own type:
Concept

Indirect recursion (1 step): The following complex types contain elements of a type, that contains elements of their own type. Both types involved will be listed:
ClassHierarchyNode / ClassHierarchyNodes
ClassHierarchyNodes / ClassHierarchyNode

Note: some other types of recursion, e.g. involving cycles of three complex types, recursion of type extension, alternations of complex types and element groups, or element groups alone are not yet reported!

Type inheritance

The SDD schema is used object-oriented inheritance mechanisms for complex types. The following tables give an overview of type derivations present in the schema.

Complex types derived by extension

(In a future version of this report it is desirable to list indirect type derivation as well!)

Complex types derived by restriction

Simple types derived by restriction

Table of annotations containing the problem marker (= '@@')

The character '@' is used inside schema annotations to mark problem or places that need further discussion. The table is sorted by order of occurrence in the schema.

(Generated by DiversitySchemaTools Version 0.4. Copyright (c) G. Hagedorn 2004.)