Core Artifact Structure

In the YAML serialization, an artifact is written as a set of keys and values. Its opening keys give the artifact's type, name, description, and identity:

type: text-field
name: Study Name
description: The name of the study
id: https://repo.metadatacenter.org/template-fields/5c2d54c

Every artifact begins this way, differing only in its type and in the content it carries. A template:

type: template
name: Study
description: A clinical study
id: https://repo.metadatacenter.org/templates/7b8977e

Or an element:

type: element
name: Address
description: A postal address
id: https://repo.metadatacenter.org/template-elements/be89d73

An instance opens the same way, and additionally identifies the template it conforms to:

type: instance
name: SDY232
id: https://repo.metadatacenter.org/template-instances/1f9a2b3
isBasedOn: https://repo.metadatacenter.org/templates/7b8977e

These four kinds fall into two families. A template, element, or field is a schema artifact, describing the shape that metadata must take. An instance is an instance artifact, holding metadata that conforms to a template. A few keys apply only to schema artifacts, since only a schema artifact defines structure.

The type Discriminator

Every definition opens with type, whose value names the artifact kind and, for fields, the field type. The reader dispatches on it. The value fixes which further keys are meaningful.

Value	Artifact
template	A template.
element	An element.
a field-type token	A field, of one of the field types below.
instance	A template instance.
element-instance	A standalone element instance.

Descriptive Keys

Key	Value	Presence	Meaning
name	string	required	The artifact's human-readable name. Required.
description	string	optional	A description of the artifact. Omitted when empty.
identifier	string	optional	An application-defined identifier, distinct from id. Not necessarily an IRI. Omitted when empty.
language	string	optional	The natural language of the artifact's content, as an IETF BCP 47 language tag (for example en). Omitted when empty.

Identity

An artifact's id is its own identifier, an IRI. The model fixes no particular form for it. Any valid IRI serves. In practice CEDAR mints identifiers under its own repository, so a CEDAR id usually looks like https://repo.metadatacenter.org/templates/7b8977e, with a path segment naming the artifact kind and a trailing identifier. An id from another source is equally valid, as long as it is a well-formed IRI.

Key	Value	Presence	Meaning
id	IRI	conditional	The artifact's own identifier. Present when the artifact has been assigned one.

A nested child is not required to have an id; when it does, it is preserved.

Field Types

A field's type is one of 25 field types, each collecting a particular kind of value.

Field type	Collects
text-field	Free text.
text-area-field	Multi-line text.
numeric-field	A number.
temporal-field	A date, time, or datetime.
controlled-term-field	A term from a controlled vocabulary.
radio-field	One option, as radio buttons.
single-select-list-field	One option, from a dropdown list.
checkbox-field	Any number of options, as checkboxes.
multi-select-list-field	Any number of options, from a dropdown list.
link-field	An IRI.
phone-number-field	A phone number.
email-field	An email address.
attribute-value-field	User-supplied attribute/value pairs.
ext-ror-field	A ROR identifier.
ext-orcid-field	An ORCID identifier.
ext-doi-field	A DOI.
ext-rrid-field	An RRID.
ext-pfas-field	A PFAS identifier.
ext-pubmed-field	A PubMed identifier.
ext-nih-grant-id-field	An NIH grant identifier.
static-rich-text	Fixed formatted text (collects no value).
static-image	A fixed image (collects no value).
static-youtube-video	An embedded video (collects no value).
static-section-break	A section divider (collects no value).
static-page-break	A page divider (collects no value).

Model Version

Every schema artifact records the version of the CEDAR model it is written against, in modelVersion. The current model version is 1.6.0. Because it names the modelling language rather than any one artifact's content, modelVersion changes only when the CEDAR model itself changes. An instance does not carry it.

Key	Value	Presence	Meaning
modelVersion	string	optional	The version of the CEDAR model the artifact conforms to (currently 1.6.0).