6.2 General Conformance Rules

6.2.1 Schema Validation 

A message is conformant to this specification only when it validates against the set of XML Schema files.

6.2.2 Allowed Value Lists 

The allowed values are listed, defined and provided through the DDEX Data Dictionary Standard in accordance with its latest version. Other values are not possible unless by using the mechanism described below:

This standard does not explicitly list allowed values. The XML Schema files contain the allowed values at the time of writing of this standard. Some of the allowed value sets contain a provision to either use a User Defined Value instead of a DDEX-defined value (in that case the MessageSender has to select the value UserDefined from the AVS and provide its own value in the XML attribute UserDefinedValue) or to augment a DDEX-defined value (in that case the MessageSender may not select the value UserDefined from the AVS but shall provide its additional information in the XML attribute UserDefinedValue). In either case the Namespace attribute shall be used to indicate where the user defined value is defined and maintained.

6.2.3 Allowed Values for Namespace Attributes 

The Namespace attributes can be used to enable message parties to use proprietary value lists.

The allowed value for the Namespace attribute which it is recommended should be used is the DDEX Party Identifier of the party controlling the proprietary allowed value, as defined in, and administered in accordance with the latest version of the DDEX Party ID Standard, DDEX-MPID.

6.2.4 Indicating Unknown Values 

When the Message Sender is required to provide a data element but cannot do so, the following values shall be entered:

  • In fields of type xs:string: “#unknown#” ;

  • In fields of type xd:date: “9999-01-01”;

  • In fields of type xs:datetime: “9999-01-01T99:01:01”; and

  • In fields of type xs:duration: “PT99H01M01S”.

The circumstances under which such behaviour is permissible may be limited in the specific business relationship between Message Sender and Message Recipient.

6.2.5 Contractually Mandatory 

The messages defined in this standard contain fields with cardinality “0-1” or “0-n”. Therefore these fields are from the standard’s point of view, optional. Such fields may, however, be mandatory when a DDEX message is sent in a specific commercial context.

In such circumstances, a message is deemed conformant only if and when it contains all the “contractually mandatory” fields as agreed by Message Sender and Message Recipient.

6.2.6 Namespace

The full namespace for the XML Schema document for this Standard is

All messages developed within DDEX are based upon a common set of elements and their definitions. These are contained in the DDEX Data Dictionary available from https://kb.ddex.net/reference-material/data-dictionaries.

6.2.7 Character Coding  

All messages shall be sent in UTF-8.