EHR & Versioning

Namespace: OpenEHR.RM.Ehr, OpenEHR.RM.Common.ChangeControl

Ehr

The top-level container representing a single patient's electronic health record. Each Ehr has a globally unique EhrId (HierObjectId).

var ehr = new Ehr
{
    SystemId    = new HierObjectId("hospital.example.com"),
    EhrId       = new HierObjectId(Guid.NewGuid().ToString()),
    TimeCreated = new DvDateTime(DateTimeOffset.UtcNow.ToString("o")),
    EhrStatus   = new EhrStatus { … },
};

EhrStatus

Carries demographic linkage, consent flags, and queryability settings for an EHR:

Property	Description
Subject	PartySelf linking to the patient
IsQueryable	Whether the record appears in population queries
IsModifiable	Whether the record can be updated

Versioning

openEHR uses a first-class versioning model. Every mutable object (Composition, EhrStatus, Folder) is wrapped in a Version<T> and grouped into a Contribution.

Contribution

Equivalent to a git commit — an atomic change-set that groups one or more Version<T> objects:

var contribution = new Contribution
{
    Uid     = new HierObjectId(Guid.NewGuid().ToString()),
    Versions = new HashSet<ObjectRef> { /* refs to the versions */ },
    Audit    = new AuditDetails
    {
        SystemId     = "hospital.example.com",
        Committer    = new PartyIdentified { Name = "Dr Smith" },
        TimeCommitted = new DvDateTime(DateTimeOffset.UtcNow.ToString("o")),
        ChangeType   = new DvCodedText { Value = "creation", DefiningCode = … }
    }
};

OriginalVersion<T>

The first or updated version of an object:

var version = new OriginalVersion<Composition>
{
    Uid             = new ObjectVersionId($"{guid}::hospital.example.com::1"),
    Data            = myComposition,
    LifecycleState  = new DvCodedText { Value = "complete", DefiningCode = … },
    CommitAudit     = contribution.Audit,
    Contribution    = new ObjectRef(contribution.Uid, "LOCAL", "CONTRIBUTION")
};

ObjectVersionId

Version IDs take the form <object_id>::<creating_system>::<version_tree_id>:

"a1b2c3d4-e5f6-7890-abcd-ef1234567890::hospital.example.com::1"

Subsequent versions increment the tree ID: ::2, ::3, etc. Branched versions use a . separator: ::1.1.1.