Attribute-Value Field

An attribute-value field collects a set of user-supplied attribute/value pairs. The instance author names each attribute and gives its value, so the field suits metadata whose properties are not known when the template is designed. In YAML its type is attribute-value-field.

The definition takes no type-specific keys, since the attribute names are not known until the instance is filled in.

- key: extra-attributes
  type: attribute-value-field
  name: Additional Characteristics

In an Instance

An attribute-value field is represented differently from other fields in instances. Its values do not sit under the instance's children. Instead the field's key becomes a top-level key of the instance, and beneath it each attribute the author supplied is paired with its value. Those attribute names are chosen by the author at fill-in time, not fixed by the template.

type: instance
name: SDY232
isBasedOn: https://repo.metadatacenter.org/templates/ec3f500
children:
  study-name:
    value: Cardiology cohort
extra-attributes:
  Batch Number:
    value: "3"
  Freezer ID:
    value: F-12

A parent may hold more than one attribute-value field. Each appears as its own top-level key, keyed by the field's key, carrying its own set of attribute-value pairs.

extra-attributes:
  Batch Number:
    value: "3"
storage-details:
  Freezer ID:
    value: F-12
  Shelf:
    value: "4"