All messages developed within DDEX are based upon a common set of elements and their definitions. These are contained in the DDEX Data Dictionary.
The data elements that are common across multiple message suites will be defined within a Baseline Schema. Individual message suites (such as the one defined by this Standard) are constructed using a combination of “local” elements (which are specific only to the message set) and common elements taken from the Baseline Schema.
Elements taken from the “Baseline Schema” have either a ddex or ddexC namespace prefix (for elements defined by DDEX) or a namespace starting with iso (for elements defined by the International Organisation for Standardisation ISO), whereas elements defined for a particular Standard have namespace prefixes specific to the particular Standard. The elements necessary for the purpose of the Catalogue Transfer Choreography Standard (as defined in this document) have the ccho namespace prefix.
The full namespace for the XML Schema document for this Standard is
The full namespaces for the relevant baseline schema files are constructed to the following schema: http://ddex.net/xml/<date>/<schema>. The applicable baseline schema files for this Standard are indicated in Annex B.
In addition to including the baseline schemas, the schema file defined by this standard includes the schema files of other DDEX standards: DDEX-AMEP and DDEX-ERNM.
W3C’s XML Schema Standard has been used to define the structure of the messages and some of the business rules. However, XML Schema alone cannot easily provide a means for complex and conditional validation but XML tools such as eXtensible Stylesheet Language Transformation (XSLT) and XPath could provide a means of developing standard validation modules for each message set.