The CDS-XML Schema Version Number Format
The use of XML has been mandated by the e-Government Interoperability Framework (e-GIF) programme as the standard to be used for messaging by government organisations and has accordingly been adopted by the NHS.
The CDS-XML Schema adopts version numbering techniques in line with published e-GOV best practice guidelines. All schema components are version numbered and date qualified; the following is an example of the adopted format:
CDS-XML_Message_Root
Example: V6-0-2007-03-01 (Note that dash separators are used).
[Schema Filename] + [Major Version Number] + [Minor Version Number] + [Version Date]
| VERSION NUMBER ELEMENT | FORMAT | EXAMPLE AND NOTES |
| Schema File Name | As allocated by NHS Data Standards | CDS-XML_Message_Root- |
| Major Version Number | A maximum of 3 numerics incremented numerically without leading zeros | V6- |
| Minor Version Number | A maximum of 3 numerics incremented numerically without leading zeros | 0- |
| Version Date | ccyy-mm-dd | 2007-03-01 |
The Major Version Number:
This is incremented when fundamental change has taken place such as:
- Major addition / deletion / change of schema business functionality
- Major change to the technical design of the schema
- Re-alignment of the Schema Version Number after cumulative changes
This is incremented for all schema changes not warranting a Major Version Number increment (as above).
Examples are:
- Minor changes to schema business functionality
- Minor changes to the schema data structures that are not upwardly compatible*
- Addition and/or deletion of data items that are not upwardly compatible*
- Changes to data item facet definitions that are not upwardly compatible*
This may be adjusted as a defined reference point for a no risk schema release to reflect minor changes and corrective releases.
Examples are:
- Minor changes to the schema data structures that are upwardly compatible* for instance the addition of an optional data item.
- Changes to data item facet definitions that are upwardly compatible* for instance the addition (but not the deletion) of code values to a data item enumeration list.
- Interim development versions, released for information only
* Upwardly Compatible:
Minor changes and adjustments to the schema which introduce little or no risk of increased data rejection are deemed upwardly compatible.
For example, corrective adjustments, which align the schema to the authorised NHS Data Standards as published in the NHS Data Model and Dictionary often fall within this category.
The Schema Date:
All schema releases have a designated SchemaDate XML Attribute.
Schema Version Control - The Schema Root:
The schema root is the single entry point to the schema and XML Attributes for the following are validated:
- SchemaVersion
- SchemaDate