Appendix

Acknowledgements

Contributors

This specification has benefited from formal and informal input from the openEHR and wider health informatics community.

Trademarks

  • 'openEHR' is a registered trademark of the openEHR Foundation

Previous Versions

This specification is based on the types originally defined in the openEHR Support Information Model from Release 1.0.3 of the Reference Model. Some changes have been made as follows.

Interval types

The additional types Point_interval and Proper_interval have been added, to support the common need for a point value and a proper interval to be specified as substitutable types. The types Multiplicity_interval and Cardinality have been added, from the AOM2 specification.

Functional meta-types

A collection of meta-types representing routines, procedures and functions has been added, to support specifications that need to use these concepts.

Amendment Record

Issue Details Raiser Completed

BASE Release 1.3.0 (unreleased)

1.3.6

Introduce the Hrid primitive type: a String constrained to the human-readable identifier (HRID) grammar defined in the {openehr_base_artefact_identification}[Artefact Identification^] specification, with segment and version accessors. Resolves the ADL 2 / Base Types HRID syntax conflict (SPECBASE-49, SPECPR-363).

S Iancu

10 Oct 2026

1.3.5

Clarify how Iso8601_duration.to_seconds() converts durations containing years and months to seconds — add the explicit conversion formula and a cross-reference to the Time_Definitions 'average' day-count constants (SPECPR-386).

P Pazos,
S Iancu

24 Jul 2026

1.3.4

Remove the timezone function from Iso8601_date: an ISO 8601 date does not carry a timezone (the time shift applies only to the time part), so the accessor — carried over from Iso8601_date_time / Iso8601_time — is removed (SPECPR-426).

J Mewes

24 Jul 2026

1.3.3

Correct documentation typos in the Overview and Time types, and remove the repeated meaning text in the Interval intersects and contains function documentation (SPECPR-458, SPECPR-459, SPECPR-460).

R Kavanagh

23 Jul 2026

1.3.2

Type the test argument of the Container predicate functions (there_exists, for_all, matching, select) as FUNCTION<TUPLE1<T>, Boolean> instead of the undefined Operation type — a UML-to-BMM omission in SPECBASE-48.

S Iancu

23 Jul 2026

1.3.1

Add BMM definition of BASE and render class asciidoc files (SPECBASE-48).

S Iancu

11 May 2026

1.3.0

Documentation fixes and typos (including SPECPR-391).

S Iancu,
P Pazos

10 Jan 2025

SPECBASE-32: Improve Types cross-reference table in Foundation types.

S Iancu

09 Jan 2025

1.2.2

SPECAM-82: Add legacy CODE_PHRASE class to Foundation Types to support AOM 1.4 model.

T Beale

26 Apr 2023

1.2.1

SPECBASE-37: Add stereotypes to represent Enums from common programming languages.

T Beale

14 May 2022

BASE Release 1.2.0

1.2.0

SPECBASE-34: Allow +14:00 timezone.

S Iancu

22 Mar 2021

SPECBASE-25: Improve and correct function definitions in Foundation types. Add 'nominal' computation functions to Iso8601_date and Iso8601_date_time. Add negative() functions to numeric classes and Iso8601_duration.

openEHR SEC

30 Apr 2020

BASE Release 1.1.0

1.1.0

SPECRM-72: Add guidance on date/time formatting, recommending extended ISO 8601 format.

B Lah

22 Nov 2018

SPECBASE-15. Add foundation types specification to BASE component.
Rename Aggregate to Container to be more consistent with current languages and also openEHR BMM.

T Beale

19 Jul 2018

SPECPUB-6. Correct UML package nesting and paths in documents; insert base parent package.

T Beale

27 Nov 2017

0.7.6

Re-organise heading structure. Remove references to ISO 11404. Rename to 'Foundation types';
added type cross-reference table.

T Beale

17 Aug 2017

0.7.0

Initial Writing. Taken from openEHR RM Release 1.0.3 Support Model

T Beale

20 May 2016

The Amendment history relevant to the original content in this specification can be found here (a fully hyper-linked version may be found on the working baseline).