Open XML standard for industrial and commercial catalogs

Jean-Marc Vanel 2001-06-26

Introduction

• leverage on XML Schema : use it to specify descriptors for categories, and inheritance among categories
• use URI's for items and categories, and set a URI naming scheme for them
• define a base category, containing roughly the common attributes of Requisite and Oracle Exchange, and a few fundamental derived categories

Review of existing DTD/XML schema for catalogs

• Oasis, http://www.xml.org/xmlorg_registry/index.shtml    : OASIS registry of all XML formats    link:www.xml.org    943 hits
• in http://www.openapplications.org/    OASIS' own format for e-Commerce, including catalogs    link:www.openapplications.org 189 hits
• www.biztalk.org    link:www.biztalk.org 683 hits
• Martsoft (www.Martsoft.com), mail sent, seems interesting;    link:www.martsoft.com  on altavista: 54 hits
• Requisite ... link:www.requisite.com   on altavista: 109 hits

http://www.ecx-xml.org/    Site for its XML exchange format
• saqqara    link:www.saqqara.com: 357 hits !!!    seems to be a serious competitor to Requisite !
• ContentEurope (http://www.contenteurope.com/)    provides cataloging services    link:www.contenteurope.com "AltaVista found no document matching your query" !!!
• Cataloga (http://www.cataloga.com)    link:www.cataloga.com    1 hit    no software, services only
• Liaison    http://www.liaison.com
• TO BE COMPLETED <<<<<<<<<<<

Requirements for XML formats for industrial catalogs

• readability
• support validation rules
• allows for easy generation of queries and searches
• supports internationalization
• extensibility: allows adding unforeseen content (e.g. tables, HTML or XML mark-up) into items and catalogs without breaking existing protocols and software
• allows for easy mappings within categories and descriptors (e.g. between original supplier data and market place data), with splitting or merging of categories
• supports mappings between different unique identifiers (part numbers), e.g. supplier and buyer having different part numbers for the same product
• support different levels of quality for catalogs (e.g. more or less details, ???)
• content generation, e.g. :
• support generation of detailed description from individual descriptors
• manage mathematical or logical relations between descriptors (e.g. power=tension*intensity*cos phi ), either as validation rule or as content generation
• support authoring information
• compatible as an extension with the main current format standards for catalog data : possible XSLT transforms with no loss of data from  current standards to OX-SICC, XSLT transforms with possible loss of data from OXSICC to current standards
• manage secondary categories for an item (indicating a hybrid product having two or more uses)
• manage keywords for items and/or categories
• manage generic descriptors (e.g. color, weight, power, etc)
• price lists : manage prices by a delegate software object as a general dependency or function of : unit price, UOM, quantity, order date, shipping date, shipping conditions, payment conditions, buyer, supplier, contract ...
• be able to represent heterogeneous catalogs (different types of items from different suppliers)
• possibility to use unambiguously several URI naming schemes for suppliers, items types, and items
• possibility for definition of suppliers, items types, items to use either URI references or inlined elements

Advantages of using W3C's XML Schema for catalogs

• flexible and powerful mechanism for specifying simple (base) types (restriction, facets, regular expressions)
• inheritance (derivation) between types
• documentation is part of the standard (contrary to DTD)
• contrary to DTD, XML Schema is simple XML syntax, and thus allows: controlled extensibility, XSLT transformations (create input or query forms, sample instance, etc.)
• mechanism for validation is standardized (concerns validation of items wrt categories)
• validation tools exist, even now when the standard is not yet finalized (XSV, XML Spy, Oracle XMLSchema java package)
• built-in support of URI's as unique identificator for the root element of a Schema
• modular and decentralized construction of Schemas by import and include

Outline of the solution

http://www.IndustrySuppliers.com/catalogs/imperator/2001#xpointer(//item[supplier_part_number='122'])

The examples given in the Annexes are short extracts from the real Schemas. We provide hereafter hints for the following features :

• choice of single supplier (not shown in Annex) and aggregated versions of catalogs and items
• content generation, using embedded fragments of XSLT
• inter-descriptor and other complex rules and constraints, using embedded fragments of Schematron
• internationalization: several <description> and <long_description> elements inside an <item>, having different xml:lang attributes.
• mappings within categories and descriptors can be specified :
• merging one or more category A within one another, B: through XML Schema extension mechanism, declare that A extends B
• splitting one category A into one or more other categories: can be specified using an embedded fragment of XSLT
• manage secondary categories for an item (indicating a hybrid product having two or more uses): use a URI reference to the secondary categories inside the <item> element, e.g. :

<item secondary='http://www.IndustrySuppliers.com/catalog/2001/01/gasket'>...</item>
• manage keywords for items and/or categories: re-use XHTML syntax and semantics from namespace http://www.w3.org/1999/xhtml , e.g.:

<xhtml:meta name="keywords" lang="en" content="reliable, high temperature">
• authoring information: Dublin Core is a standard that can be reused: Creator, etc., inside <xhtml:meta> elements
• possibility for definition of suppliers, items types, items to use either URI references or inlined elements: example:

<item><supplier ref='www.legrand.fr'/>...</item>
• manage generic descriptors (e.g. color, weight, power, etc.): a library of reusable generic descriptors can be set as an XML Schema containing first-level element definitions; it can be very useful for search engines; here is an example of reusing a generic descriptor in a category definition:

<xsd:element ref="isc:weight" />
• price lists : manage prices by a delegate software object as a general dependency or function of : unit price, UOM, quantity, order date, shipping date, shipping conditions, payment conditions, buyer, supplier, contract ...

This remains to be defined, but a general solution could be to indicate the URL of a jar file containing an object that does the computation. The argument to the function will be, for maximum flexibility, an XML string or corresponding DOM object, those XML Schema will specify all the above information. So the function signature would just be :
org.w3c.DOM.Document message(org.w3c.DOM.Document doc);
which is a general and re-usable architecture for flexible communication.

URI naming schemes

As we said, the unique identifier of a category is the URI of the corresponding schema. The naming scheme will be composed of:

• the URI of company or organization (as above) defining the category
• a part defined by the company or organization, ending with the english name in singular form of the category

For items, a URI will be made using :

• the URI of the supplier (or of the market place)
• a catalog name or year
• an XPointer - XPath expression using the primary key(s) dor the item

Issues

• Synonyms in URI:
• several URL's for a single company
• several URL's for a single item

URI for an item will be "baptized" by the supplier or the market place, but who will "baptize" the trading organizations and companies ?
• TO COMPLETE <<<<<<<<<<<<<

Compatibility with existing standards

Annex 1 - Schema for base category

The actual schema will contain more details, but this is a short (but valid) sample to show the essentials.

<xsd:schema targetNamespace="http://www.IndustrySuppliers.com/catalog/2001/01"
  xmlns:isc="http://www.IndustrySuppliers.com/catalog/2001/01"
  xmlns:xsd="http://www.w3.org/2000/10/XMLSchema"
  elementFormDefault="qualified"
  attributeFormDefault="qualified"
>
  <xsd:complexType name="category">
    <xsd:annotation>
      <xsd:documentation>Template for common and mandatory information about a catalog item.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:all>
      <xsd:element name="supplier" type="xsd:string" />
      <xsd:element name="supplier_part_number" type="xsd:string"/>
      <xsd:element name="description" type="xsd:string"/>
      <xsd:element name="long_description" type="xsd:string" />
    </xsd:all>
  </xsd:complexType>

  <xsd:complexType name="catalog">
    <xsd:sequence>
      <xsd:element name="item" type="isc:category" maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="catalog" type="isc:catalog" >
   <xsd:unique name="supplier_part_number">
    <xsd:selector xpath="item"/>
    <xsd:field xpath="supplier"/>
    <xsd:field xpath="supplier_part_number"/>
   </xsd:unique>
  </xsd:element>

</xsd:schema>

Annex 2 - Schema for derived category

  <xsd:element name="gasket" type="gasket">
    <xsd:annotation>
      <xsd:documentation>
        IndustrySuppliers.com's definition of a gasket item
        belonging to an industrial catalog.</xsd:documentation>
    </xsd:annotation>
  </xsd:element>

  <xsd:complexType name="gasket">
    <xsd:complexContent>
      <xsd:extension base="isc:category">
        <xsd:all>
          <xsd:element name="diameter" type="xsd:float" minOccurs='1' />
        </xsd:all>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

</xsd:schema>

Annex 3 - Sample XML instance of industrial catalog

<?xml version='1.0' encoding='ISO-8859-1'?>
<catalog
xmlns       ='http://www.IndustrySuppliers.com/catalog/2001/01'
xmlns:gasket='http://www.IndustrySuppliers.com/catalog/2001/01/gasket'
xsi:schemaLocation='http://www.IndustrySuppliers.com/catalog/2001/01/gasket
                    gasket.xsd'
xmlns:xsi='http://www.w3.org/2000/10/XMLSchema-instance'
>
  <item xsi:type='gasket:gasket'>
    <supplier>Imperator</supplier>
    <supplier_part_number>122</supplier_part_number>
    <long_description>Very good indeed!</long_description>
    <description>Very good!</description>
    <gasket:diameter>1.22</gasket:diameter>
  </item>
</catalog>

Annex 4 - Glossary and acronyms

Annex 5 - References

XML Schema specification:
http://www.w3.org/TR/xmlschema-0/
http://www.w3.org/TR/xmlschema-1/
http://www.w3.org/TR/xmlschema-2/
XML Schema Tutorial

Command-line tool for validating with XML Schema: XSV
Current Status of XSV: Coverage, Known Bugs

Schematron specification:
http://www.ascc.net/xml/resource/schematron/
Schematron tutorial:
http://www.zvon.org/index.php?nav_id=2
TO COMPLETE <<<<<<<<<<<<<

Annex 6 - expressing validaty rules inside the XML Schema

        <xsd:simpleType>
         <xsd:restriction base="xsd:string">
          <xsd:length value="8"/>
          <xsd:pattern value="\d{3}-\d{4}"/>
         </xsd:restriction>
        </xsd:simpleType>