The use of XML was mandated by the e-Government Interoperability Framework (e-GIF) programme as the standard to be used for messaging by government organisations and accordingly this has been adopted by the NHS.
For the most part, the XML Schema applies the data specifications as authorised by the NHS and documented in the NHS Data Model and Dictionary.
The Issued Documentation
The NHS Digital Data Architecture Team maintain and issue the following XML Schema documentation:
- The XML Schema Files (generated using ALTOVA XMLSPY ©)
The XML Schema files consist of a series of interpretable XML/HTML statements which define the data structures and content rules for the use of the message. User systems use the XML Schema to either populate or interpret an 'XML Schema instance' that is the resultant XML formatted message file which carries the data.
The XML Schema therefore represents the 'design' of the message and it may be necessary therefore to interpret and understand the information inherent in the XML Schema file code.
- The XML Schema Documentation (generated using ALTOVA XMLSPY ©)
These files are generated using XMLSPY software and may be read in any browser, e.g. Microsoft Edge©. The files consist of a 'root' entry HTML formatted file and a (usually) large number of supporting .png graphic files used by the root HTML.
This documentation enables useful "drill down" functions for investigating structures and data items, but these features are not as powerful as when using a full XML Schema editor (see below).
Most browsers will support printing and thus the XML Schema details can be printed as required but users are warned that browser based prints often generate a large number of pages.
The CDS XML Schema generates approximately 450+ pages of details, printing is therefore not advised.
- The XML Schema Release Notes
This is a pdf document identifying the changes applied to the XML Schema release, from the previous release.
References to Information Standards Notices and other technical change requirements are detailed.
Reading XML Schema
Whilst XML Schemas can be read as HTML in most browsers, it may be difficult to fully interpret the XML Schema unless the reader has a detailed understanding of HTML.
It is recommended that XML Schemas are read using an XML interpreter (such as ALTOVA XMLSPY ©), many of these are freely available on the internet.
XML Schema technicians may prefer to use such software to examine XML Schemas more deeply as the interactive facilities provided are generally more powerful than browsing the XML/HTML supplied Schema code.